Twenty-Three Years of Insect Pollinator-Dependent Crop Studies in Agro-Ecological Zones of Cameroon (2011-2020)

Népidé Ndobadé Carine^1*, Egono Ndemé Carole Christèle², Daniel Farda¹, Mazi Sanda³

¹Department of Animal Production, School of Veterinary Medicine and Sciences, University of Ngaoundéré, Ngaoundéré, Cameroon.
²Department of Environmental Sciences, Higher Institute of Agriculture Wood, Water and Environment, University of Bertoua, Bertoua, Cameroon.
³Department of Biological Sciences, Faculty of Science, University of Ngaoundéré, Ngaoundéré, Cameroon.

DOI: 10.4236/as.2024.158049                

Abstract

Cultivation of pollinator-dependent crops has expanded globally, increasing our reliance on insect pollination. This essential ecosystem service is provided by a wide range of managed and wild pollinators whose abundance and diversity are thought to be in decline, threatening sustainable food production. In Cameroon, several studies on pollinator-dependent crops carried out in different agro-ecological zones (AEZ) have been published in national and international journals, in order to present the importance and impact of flowering insects on fruit and seed yields of plant species. We proposed to produce a review article highlighting the different flowering insects and their importance for different plants according to AEZ, without however focusing on the quality of the journal (predator or non-predator) and how the different insects were identified (scientific names given in the publications). Thus, from 1997 to 2020, we collected 116 published papers from which only 26 were kept for this review. The results show that Hymenoptera, including the Apidae, followed by Megachilidae, are the most excellent pollinators of plant species in Cameroon, and they are present in different agro-ecological zones. The majority of publications focused on bees, particularly the honeybee Apis mellifera.

Keywords

Agro-Ecological Zones, Cameroon, Flowering Insects, Hymenoptera, Pollinators

1. Introduction

Entomophilic pollination is a key component of ecosystem functioning and is therefore an ecosystem service of global importance [1]. For most Angiosperm plant species, reproduction depends on pollination provided by a wide range of animal species, including insects, birds and mammals [2]. This type of pollination is characterised by the transport of pollen grains from the stamens to the stigmas of the pistil of flowering plants by insects. This process is an essential step in plant fertilisation. More than 200,000 species of flowering plants depend on pollination by more than 100,000 species of insects [3]. Pollination by flower-feeding insects is vital for maintaining biodiversity worldwide [4]. Pollinators, including bees, contribute efficiently to food security and nutrition, sustainable agriculture, the health of ecosystems and the environment, the preservation and enrichment of biological diversity and other aspects of sustainable development [5]. Cameroon is subdivided into five (05) major agro-ecological zones due to its geographical position and its diversity of soils and climates [6]. As a result, several studies on plant-insect interactions in different agro-ecological zones (Forest zone with monomodal rainfall, Forest zone bimodal rainfall forest, Western highlands, Guinean high savannah and Sahelo-Sudanian) have been published. This was done with a view to highlighting the importance and impact of flower visiting insects on fruit and seed yields [7] [8] in Cameroon. As the expansion of pollinator-dependent crops in certain regions of the world has been analyzed in the paper [9] [10], where pollination research is well documented with tremendous publications. However, in Africa in general and in Cameroon in particular, the field is still at its infancy with the first works in early 1990s and thereafter has rapidly grown the last 20 years. Thus, research has been carried out in all five agro-ecological zones in the country, with the greatest concentration of work in the High Guinean Savannah. The present work is a synthesis of scientific articles presenting the impact and/or contribution of pollinating insects on fruit and seed yields in agro-ecological zones of Cameroon. The aim of this work is to present the diversity of insect pollinators and the plants benefiting from them, without however focusing on the quality of the journal (predator or not) where the papers were published.

2. Methodology

To shed light on the dynamics of publications related to plant-insect pollinator interactions in Cameroon, various scientific articles were used. Due to the fact that there is no technical report published, our documentation criteria included all articles and books online or published before 25 October 2023. The articles were obtained through Scopus and Google Scholar. Our literature searches were done in English and French as both languages are the national languages in Cameroon, and publications as done in both. We also obtained some publications from the library of the Applied Apidology Unit of the Faculty of Science of the University of Ngaoundéré in Cameroon.

The methodology adopted is summarised in Figure 1 below.

Figure 1. Selection method for scientific publications.

Our selection criteria are as follow: 1) repetition of the study over time (at least 2 years); 2) plant yields; 3) location of the work; 4) plant family repeated over time.

From 1997 to 2020, 116 scientific articles were selected, irrespective of the language of publication and the scientific journal. Subsequently, 33 articles were subtracted from this initial total, in particular those whose data had not been repeated over time. Then 23 articles that did not present parameters related to plant species yields were excluded; followed by 2 articles that did not belong to any agro-ecological zone in Cameroon and finally 7 articles that did not have repeated plant families and agro-ecological zones. In the end, based on the repeated plant families and agro-ecological zones of Cameroon, 26 publications were selected for the period from 2011 to 2020, and used for the present work. Figure 2 below shows a map of Cameroon with the different agro-ecological zones.

The map shows that Cameroon is subdivided into five agro-ecological zones (AEZ): Sudan-Sahelian; Guinean High Savannah; Forest with bimodal rainfall regime; Forest with monomodal rainfall regime; Western High Plateaux.

Figure 2. Maps of Cameroon’s agro-ecological zones.

3. Results and Discussion

Data from the synthesis of scientific articles are summarised in supplementaries 1 to 5, which show that studies on the impact of pollinating insects on fruit and seed yields of plant species were carried out in the five (05) agro-ecological zones (AEZ) in Cameroon (Figure 2).

The following figure (Figure 3) shows the number of articles published by agro-ecological zone.

Figure 3. Data synthesis in agro-ecological zones.

Figure 4 presents the data summary in forest zone with the monomodal rainfall.

Figure 4. Summary of forest zone with the monomodal rainfall.

In the agro-ecological forest zone with monomodal rainfall (Supplementary 1, Figure 4), two (02) plant families were studied: Fabaceae and Pedaliaceae. On Fabaceae (Vigna unguiculata) plants, Hymenoptera ranked first with pollinator insects belonging to Apidae family which include the following insects: Apis mellifera, Xylocopa olivacea and Amegilla sp., followed by Megachilidae family (Chalicodoma sp. and Megachile sp.). These insects are the main pollinators of the plant in this AEZ. The same species (Apis mellifera, Xylocopa olivacea, Amegilla sp. (Apidae)) and Chalicodoma sp., Megachile sp. (Megachilidae) are the main pollinators of Pedaliaceae (Sesamum indicum) plant. For the Fabaceae plant, the yield due to flowering insects was 92.22% for the fruiting rate and 91.01% for the percentage of normal seeds. For the Pedaliaceae, the corresponding values were 75.55% and 88.45% respectively. These results show that for both plant families, Apidae and Megachilidae are the main pollinators in that zone. Moreover, the equatorial cameroonian climate would favour the activity of flowering insects. The contribution of bees, particularly honeybees (Apis mellifera unicolor), to plant pollination has also been noted by researchers [11] in a humid tropical forest formation in Reunion and Madagascar.

Figure 5 presents the data summary in forest zone with the bimodal rainfall.

In the bimodal rainfall forest zone (Supplementary 2, Figure 5), only one (01) plant family has been studied: the Fabaceae with three different plants (Phaseolus coccineus, Cajanus cajan and Vigna unguiculata). In this zone, Hymenoptera ranked first, and Apidae (Xylocopa calens, Xylocopa albiceps, Apis mellifera adansonii, Dactylurina staudingeri, Xylocopa torrida, Xylocopa nigrita, (1 sp.), Meliponula erythra, Xylocopa olivacea, Allodape sp. and Meliponula bocandei); followed by Megachilidae (Chalicodoma cinta cinta, Megachile bituberculata, Chalicodoma rufipennis, Chalicodoma rufipes and Chalicodoma torrida), are the most important pollinators. The mean fruiting rate was 85.31% and the mean percentage of normal seeds was 93.56%. Therefore for both plant families, Apidae and Megachilidae are the main. The equatorial Guinean climate

Figure 5. Summary of forest zone with the bimodal rainfall.

would have a positive influence on the activity of flowering insects. Thus, the forest zone is of crucial importance for the pollinator’s diversity and improves the pollination of adjacent crops [12].

Figure 6 presents the data summary in the Guinean high savannas zone.

Figure 6. Summary of the Guinean high savannas zone.

Concerning the Guinean high savannas zone (Supplementary 3, Figure 6), studies were concentrated on five (05) plant species families: Fabaceae (Phaseolus vulgaris, Phaseolus coccineus, Glycine max, Cajanus cajan and Vigna unguiculata), Malvaceae (Gossypium hirsutum), Euphorbiaceae (Croton macrostachyus), Solanaceae (Physalis minima) and Pedaliaceae (Sesamum indicum and Cerathoteca sesamoides). Hymenoptera are the main pollinators for Fabaceae, with the Apidae (Xylocopa olivacea; Xylocopa sp.; Apis mellifera adansonii; Amegila sp. 1; Amegila sp. 2; Braunsapis sp.; Ceratina sp. 1; Ceratina sp. 2), followed by the Megachilidae (Megachile sp., Chalicodoma cinta cinta, Chalicodoma rufipes and Chalicodoma torrida). The mean fruiting rate was 85.12% and the mean percentage of normal seeds was 89.45%. For Malvaceae plant species, Apidae (Apis mellifera adansonii; Allodope sp.; Amegilla sp. 1; Amegilla sp. 2; Tetralonia sp.) are the main pollinators. The mean fruiting rate is 93.54% and the mean percentage of normal seeds is 94.06%. Among Euphorbiaceae plant species recorded, we have the following Apidae: Apis mellifera adansonii; Meliponula furruginea; Xylocopa olivacea. The fruiting rate is 28.76% and the percentage of normal seeds is 64.14%. For Solanaceae Apis mellifera; Amegilla sp.1; Amegilla sp. 2; Ceratina sp.1; Dactylurina staudingeri; Lipotriches collaris; Lipotriches sp.1; Lasioglossum sp.1; Meliponula ferruginea were the main pollinators. The tropical Sudanian climate would favour the activity of flowering insects.

Figure 7 presents the data summary in the Sahelo-Sudanian zone.

Figure 7. Summary of the Sahelo-Sudanian zone.

With regard to the Sahelo-Sudanian zone (Supplementary 4, Figure 7), three (03) families of plant have been subject to publications: Fabaceae (Phaseolus vulgaris, Glycine max and Vigna unguiculata), with Apidae (Apis mellifera adansonii; Amegilla sp.; Thyrus sp.; Xylocopa sp.) and the Megachilidae (Chalicodoma sp., Megachile sp. and Megachile eurymera) as the main pollinators. The mean fruiting rate was 65.89% and the mean percentage of normal seeds was 63.35%. On Malvaceae (Gossypium hirsutum) plant largely cultivated as the main cash crop in that AEZ, Apidae (Apis mellifera adansonii; Allodape sp.; Amegilla sp. 1; Amegilla sp. 2; Thyrus sp.; Xylocopa sp. 1; Xylocopa sp. 2) and the Megachilidae (Chalicodoma sp., Chalicodoma kamerunensis, Megachile sp. and Creightonella sp.) are the main and efficient pollinators. The mean fruiting rate is 92.47% and the mean percentage of normal seeds is 90.84%. Concerning Euphorbiaceae (Ricinus communis) plant species, Lepidoptera ranked first with: Eurema sp.; Acraea acerata; Catopsilia florella; and one non determine Lepidoptera species (1 sp.). The fruiting rate was 96.00% and the percentage of normal seeds was 94.13%. These results show that for the three plant families, Apidae and Megachilidae are the main pollinators in the Sahelo-Sudanian agro-ecological zone. The tropical Sudano-Sahelian climate would be beneficial to the activity of flowering insects. Similarly, in Burkina Faso, the work of some researchers [1] has shown that bees have contributed to the production of the main cash crops grown by farmers in the region.

Figure 8 presents the data summary in the western highlands zone.

Figure 8. Summary of the western highlands zone.

In the western highlands zone (Supplementary 5, Figure 8), Solanaceae (Physalis micrantha) plants were studied. The main pollinators are Apidae with Amegilla sp.; Apis mellifera adansonii; Braunsapis sp.; Ceratina sp.; Dactylurina staudingeri; Lasioglossum atricum; Melipoluna erythra, occupying the first places of the Arthropods visiting the plant species. The values corresponding to the fruiting rate and the percentage of normal seeds are 65.40% and 98.64% respectively. These values reveal the positive contribution of entomophilic pollination to flowering plant yields [1]. So the equatorial cameroonian climate would favour the activity of flowering insects. Moreover, the dependence of flowering plants on pollinators has also been highlighted in the Qinghai-Tibet plateau region of China [13].

4. General Discussion

It appears that the Apidae and Megachilidae are excellent pollinators of plant species in the agro-ecological zones of Cameroon. However, the main potential pollinators are distributed differently in AEZ due to environmental conditions [14]. The general factors that influence the activity of pollinating insects include climate (temperature and humidity); the presence of attractive flowering plants; and the availability and accessibility of floral products. Good humidity and temperature conditions are favourable for foraging by Hymenoptera [15]. In addition, the presence of flowering plants that are attractive to flowering insects increases the number of flowers visited, increasing the probability of stigmatic contacts and, consequently, pollination opportunities [16]. Moreover, the presence of flower visiting insects on plants would suggest the availability and accessibility of floral products [17]. Furthermore, researchers [18] noted that the scarcity of visitors and the low efficiency of pollinators reduce the yield success of plant species. In addition, the dependence of a plant species family on insect pollinators may differ from one AEZ to another, notably due to variations in soil nutrients, microclimate and the status of pests and plant diseases [19]. This dependence could also differ between varieties of plant species [20]. This is the case for the dependence of flowering insects on oilseed rape, where researchers [21] recorded a dependence on pollinators of 30%; while other researchers [22] recorded a dependence of 20% for two varieties of the same crop. Furthermore, according to researchers [2], almost 94% of tropical plants depend on animal pollination for fruit/seed production. Pollinators are therefore essential for the reproduction of plant, as they help to preserve biodiversity and increase crop productivity. In addition, work in Kenya [23] has shown that fruit set in Persea americana is highly dependent on insect pollination, and that pollinator supplementation reduces pollination deficits in small-scale avocado production systems. Moreover, according to researchers [24], pollination deficit can compromise fruit yield and quality. This is an ample evidence of the important role played by bees in pollinating Pyrus sinkiangensis in China [24]. In Egypt, some researchers [25] showed Apis mellifera and Megachile sp. bees to be the most abundant pollinators of Egyptian clover. Similar studies on the role and importance of pollinators, particularly bees, on the yield and fruit quality of cultivated plants such as watermelon (Citrullus lanatus) and okra (Abelmoschus esculentus) were also carried out in southern Benin by researchers [26] [27]. Therefore, the presence of Apidae and Megachilidae in the different agro-ecological zones mentioned above would be due to the fact that bees adjust their behaviour to weather conditions in order to survive, and therefore to participate in the pollination of plant species. Thus, meteorological characteristics, vegetation and human activities seem to play an important role in the composition and importance of pollinating insects [14].

5. Conclusions

The results of these published studies provide ample evidence of the significant contribution of pollinating insects, especially Apidae and Megachilidae, in improving the quality of plant yields. However, their decline could have a negative impact on the ecosystem, hence the importance of preserving them.

Based on these finding and according to the research in the field of pollination ecology in Cameroon, there is an urgent need to increase research on pollinator-dependent crops, the abundance of pollinators in agro-ecological zones, as well as to identify the taxonomy of functional pollinators and their richness. Moreover, with regard to pollinators decline, we advise to look into the causes of decline such habitat defragmentation, agricultural intensification and the misuse of agrochemical by farmers, and to find ways for their sustainable management and conservation. Furthermore, given the increasing research in pollination study program in this country, it’s time to include policy makers and farmers to inform them about the importance of pollinators, as up to now, there is little public and/or political awareness of the importance of pollinators. Farmers as main actors in close relation to environment, are unaware of the role of pollinators and how to manage for them. So public authorities should set up platforms to train farmers to understand the role of pollinators and learn how to manage them for agriculture. The use of pesticides should be banned in favour of biological control.

Supplementary Materials

Supplementary 1. Yields as a function of plant families in the forest agro-ecological zone with monomodal rainfall in Cameroon.

Plants	Years and references	Months	Flora Entomofauna			Impact of flower-feeding insects on the fruit and seed yields of the plants studied
						Yields			Numerical contributions (%)
						FR (%)	MNS/F	PNS (%)	FR	MNS/F	PNS
Fabaceae family
			Order	Family	Genus, species, sub-species
Vigna unguiculata	Pharaon et al., 2019	April - July	Diptera	Calliphoridae	(1 sp.)	92.22	8.00	91.01	7.20	18.81	3.10
				Muscidae	Musca domestica
			Hymenoptera	Apidae	Apis mellifera
					Xylocopa olivacea
					Amegilla sp.
				Formicidae	(1 sp.)
				Megachilidae	Chalicodoma sp.
					Megachile sp.
				Vespidae	Synagris cornuta
			Lepidoptera	Acraeidae	Acraea acerata
				Pieridae	Catopsilia flerella
			Orthoptera		(1 sp.)
			Nevroptera		(1 sp.)
Pedaliaceae Family
			Order	Family	Genus, species, sub-species
Sesamum indicum	Pharaon et al., 2018	March - June	Diptera	Calliphoridae	(1 sp.)	75.55	58	88.45	21.08	14.70	5.02
				Muscidae	Musca domestica
			Hymenoptera	Apidae	Apis mellifera
					Xylocopa olivacea
					Amegilla sp.
				Eumenidae	Delta sp.
				Formicidae	(1 sp.)
				Halictidae	Lasioglossum sp.
				Megachilidae	Chalicodoma sp.
					Megachile sp.
				Vespidae	Synagris cornuta
			Lepidoptera	Acraeidae	Acraea acerata
				Pieridae	Catopsilia flerella
				Nymphalidae	(1 sp.)
			Orthoptera		(1 sp.)
			Nevroptera		(1 sp.)

FR: Fruiting Rate; MNS/F: Mean Number of Seeds per Fruit; PNS (%): Percentage of Normal Seeds; sp: undetermined species.

Supplementary 2. Yields as a function of repeated plant families in the forest agro-ecological zone with bimodal rainfall in Cameroon.

Plants

Years and references

Months

Flora Entomofauna

Impact of flower-feeding insects on the fruit and seed yields of the plants studied

Yields

Numerical contributions (%)

FR (%)

MNS/F

PNS (%)

FR

MNS/F

PNS

Fabaceae family

Order

Family

Genus, species, sub-species

Phaseolus coccineus

Pando et al., 2011a

May - July (2008) April - June (2009)

Hymenoptera

Apidae

Xylocopa calens

82.29

6.47

90.08

19.09

8.10

18.09

-

-

Xylocopa albiceps

-

-

Apis mellifera adansonii

-

-

Dactylurina staudingeri

-

-

Xylocopa torrida

-

-

Xylocopa nigrita

-

-

(1 sp.)

-

Megachilidae

Chalicodoma cincta cincta

-

-

Megachile bituberculata

-

-

Chalicodoma rufipennis

-

Halictidae

Crocisaspidia chandleri

-

-

Thrinchostoma wissmanni

-

-

Lasioglossum sp.

-

Vespidae

Synagris cornuta

-

Sphecidae

Philanthus triangulum

-

Formicidae

Camponotus flavomarginatus

Cajanus cajan

Pando et al., 2011b

September - October (2008) July - August (2009)

Hymenoptera

Apidae

Xylocopa calens

89.52

5.96

94.96

11.82

18.53

8.84

-

Xylocopa torrida

-

Xylocopa albiceps

-

Xylocopa nigrita

-

Apis mellifera adansonii

-

Dactylurina staudingeri

-

Meliponula erythra

-

(1 sp.)

Megachilidae

Chalicodoma cincta cincta

-

Chalicodoma rufipes

-

Chalicodoma torrida

-

Chalicodoma rufipennis

-

Megachile bituberculata

Halictidae

Crocisaspidia chandlerie

Formicidae

Camponotus flavomarginatus

Sphecidae

Philanthus Triangulum

Xymonidae

Synagris cornuta

Vespidae

Belonogaster juncea juncea

Vigna unguiculata

Pando et al., 2013

April - July

Hymenoptera

Apidae

Xylocopa olivacea

80.69

17.83

93.67

22.48

20.08

14.84

Xylocopa torrida

Xylocopa nigrita

Xylocopa albiceps

Apis mellifera adansonii

Allodape sp.

Dactylurina staudingeri

Meliponula erythra

Megachilidae

Chalicodoma cincta cincta

Chalicodoma rufipennis

Megachile bituberculata

Halictidae

Crocisaspidia chandleri

1sp.

Sphecidae

Philanthus triangulum

Vespidae

Synagris cornuta

Belonogaster juncea juncea

sp.1

sp.2

sp.3

Polistes sp.

Formicidae

Camponotus flavomarginatus

Cajanus cajan

Tchuenguem et al., 2014a

July 2008 - January 2009 June - Décember (2009)

Hymenoptera

Apidae

Xylocopa olivacea

88.76

5.96

95.55

14.64

23.48

9.43

Xylocopa torrida

Xylocopa albiceps

Apis mellifera adansonii

Meliponula erythra

Meliponula bocandei

Dactylurina staudingeri

Megachilidae

Chalicodoma cincta cincta

Chalicodoma rufipennis

Chalicodoma rufipes

Chalicodoma torrida

Megachile bituberculata

Halictidae

Crocisaspidia chandleri

(sp. 1)

Formicidae

Camponotus flavomarginatus

Sphecidae

Philanthus triangulum

Xymonidae

Synagris cornuta

Vespidae

Belonogaster juncea juncea

(sp. 2)

FR: Fruiting Rate; MNS/F: Mean Number of Seeds per Fruit; PNS (%): Percentage of Normal Seeds; sp: undetermined species.

Supplementary 3. Yields as a function of plant families in the high Guinean savannah agro-ecological zone of Cameroon.

Plants

Years and references

Months

Flora Entomofauna

Impact of flower-feeding insects on the fruit and seed yields of the plants studied

Yields

Numerical contributions (%)

FR (%)

MNS/F

PNS (%)

FR

MNS/F

PNS

Fabaceae family

Order

Family

Genus, species, sub-species

Phaseolus vulgaris

Kingha et al., 2012

June - July

Hymenoptera

Apidae

Xylocopa olivacea

88.75

6.36

92.18

73.31

18.79

26.85

Xylocopa sp.

Apis mellifera adansonii

Amegila sp. 1

Amegila sp. 2

Braunsapis sp.

Ceratina sp. 1

Ceratina sp. 2

Halictidae

Lasioglossum sp.

Megachilidae

Chalicodoma rufipes

Megachile sp. 1

Megachile sp. 2

Megachile sp. 3

Megachile sp. 4

Megachile sp. 5

Formicidae

Camponotus flavomarginatus

Camponotus sp.

Lepidoptera

Pieridae

Eurema sp. 1

Eurema sp. 2

Lycaenidae

(sp. 1)

(sp. 2)

Hesperiidae

Lambrix sp.

Syrphidae

Episyrphus sp.

Meloidae

Coryna sp.

Phaseolus coccineus

Tchuenguem et al., 2014b

June - July (2010) July - August (2011)

Hymenoptera

Apidae

Xylocopa olivacea

96.25

5.17

90.62

53.52

64.29

76.62

Ameglia sp. 1

Ameglia sp. 2

Ceratina sp.

Megachilidae

Megachile sp. 1

Megachile sp. 2

Megachile sp. 3

Vespidae

Belonogaster juncea

Polistes sp.

Lepidoptera

Pieridae

Eurema sp.

Lycaenidae

Espèce 1

Espèce 2

Espèce 3

Coleoptera

Meloidae

Coryna sp.

Lagriidae

Lagria villosa

Glycine max

Kengni et al., 2015a

March - September

Coleoptera

Meloidae

Coryna sp.

85.75

2.01

92.26

23.78

55.36

25.90

Diptera

Muscidae

Musca domestica

Syrphidae

Epysyrphus balteatus

Hymenoptera

Apidae

Apis mellifera adansonii

Ceratina sp.

Formicidae

Camponotus acvapimensis

Halictidae

Lasioglossum sp.

Vigna unguiculata

Kengni et al., 2015b

April - August (2011) March - September (2012)

Coleoptera

Pentatomidae

(1 sp.)

57.49

14.68

96.35

60.77

52.39

11.41

Meloidae

Coryna sp.

Diptera

Muscidae

Musca autumnalis

Musca domestica

Syrphidae

Episyrphus sp.

Hymenoptera

Apidae

Apis mellifera adansonii

Xylocopa olivacea

Formicidae

Camponotus acvapimensis

Myrmicaria opaciventris

Megachilidae

Chalicodoma cinta cinta

Crocisaspidia chandleri

Lepidoptera

Pieridae

Eurema sp.1

Hespiridae

Pelopidas mathias

Phaseolus vulgaris variété Bigarrée

Déli et al., 2020

June

Hymenoptera

Apidae

Apis mellifera

86.66

2.76

72.96

36.01

23.42

42.24

Amegilla acraensis

Amegilla sp.

Ceratina sp.

Tyreus sp.

Xylocopa inconstans

Xylocopa olivacea

Halictidae

Lasioglossum sp.

Megachilidae

Chalicodoma rufipes

Megachile torrida

Pieridae

Eurema sp.

Cajanus cajan

Zra et al., 2020b

April - Décember

Diptera

Syrphidae

Episyrphus sp.

95.83

4.45

92.31

23.56

41.95

26.41

Hymenoptera

Apidae

Amegilla sp.

Apis mellifera

Ceratina sp.

Dactylurina staudingeri

Meliponula ferruginea

Tyreus sp.

Xylocopa inconstans

Xylocopa olivacea

Xylocopa sp.

Formicidae

Polyrhachis sp.

Halictidae

Crocisaspidia chandleri

Lasioglusum sp.

Macronomia vulpina

Megachilidae

Chalicodoma cincta

Chalicodoma sp.

Megachile acraensis

Megachile torrida

Megachile sp. 1

Megachile sp. 2

Megachile sp. 3

Megachile sp. 4

Megachile sp. 5

Megachile sp. 6

Megachile sp. 7

Megachile sp. 8

Pachyanthidium bouyssoui

Crabronidae

Philanthus triangulum

(1 sp.)

Vespidae

Belonogaster juncea

(sp. 1)

(sp. 2)

Lepidoptera

Lycaenidae

(1 sp.)

Malvaceae Family

Order

Family

Genus, species, sub-species

Gossypium hirsutum

Mazi et al., 2013

August - September (2009) August - October (2010)

Hymenoptera

Apidae

Apis mellifera adansonii

90.41

26.70

94.82

55.74

22.04

51.20

Allodope sp.

Amegilla sp. 1

Amegilla sp. 2

Tetralonia sp.

Halictidae

Lasioglossum sp.

Lipotriches blandula

Halictus sp.

Leuconomia granulate

Formicidae

Myrmicaria opaciventris

Camponotus sp.

Paratrechina longicornis

(1 sp.)

Vespidae

Belonogaster juncea

Coleoptera

Coccinellidae

Cheilomenes lunata

Curculionidae

(sp.1)

(sp.2)

Scarabeidae

(sp.1)

Diptera

(sp.1)

Hemiptera

Pentatomidae

Nezara viridula

Coreidae

Anoplocnemis curvipes

Lepidoptera

Pieridae

Eurema sp.

Catopsilia florella

Nymphalidae

Neptis sp.

(1 sp.)

Gossypium hirsutum

Mazi et al., 2020a

September - October

Hymenoptera

Apidae

Amegilla sp.

96.67

25.39

93.30

8.63

16.15

10.21

Amegilla calens

Apis mellifera

Ceratina sp.

Halictidae

Lasioglusum sp.

Lipotriches sp.

Euphorbiaceae Family

Order

Family

Genus, species, sub-species

Croton macrostachyus

Népidé & Tchuenguem, 2016

May - June

Coleoptera

Chrysomelidae

(1 sp.)

28.76

01.33

64.14

26.85

15.24

43.49

Lycidae

Lycus latissimus

Scarabeidae

(1 sp.) (ne)

Diptera

Calliphoridae

Calliphora sp. 1

Calliphora sp. 2

Syrphidae

(1 sp.)

(1 sp.)

Hemiptera

Pyrrhocoridae

Dysdercus voelkeri

Hymenoptera

Apidae

Apis mellifera adansonii

Meliponula furruginea

Xylocopa olivacea

Formicidae

Camponotus brutus

Polyrachis sp.

(1 sp.)

Sphecidae

Philanthus triangulum

Vespidae

Belonogaster juncea

Zygenidae

(1 sp.)

Solanaceae Family

Order

Family

Genus, species, sub-species

Physalis minima

Djakbé et al., 2017

April – August

Diptera

Calliphoridae

(1 sp.)

94.44

140.97

98.33

7.06

11.91

1.61

Hemiptera

Pentamidae

(1 sp.)

Hymenoptera

Apidae

Apis mellifera

Amegilla sp.1

Amegilla sp. 2

Ceratina sp.1

Dactylurina staudingeri

Lipotriches collaris

Lipotriches sp.1

Lasioglossum sp.1

Meliponula ferruginea

Formicidae

Camponotus flavomarginatus

Halictidae

Halictus sp.1

Halictus sp. 2

Vespidae

Belonogaster juncea

(1 sp.)

Pedaliaceae Family

Order

Family

Genus, species, sub-species

Sesamum indicum

Tchuenguem & Népidé, 2018

September (2013) & July (2014)

Hymenoptera

Apidae

Apis mellifera

81.66

45.34

62.40

30.33

29.65

9.34

Ceratina sp.

Xylocopa olivacea

Formicidae

Polyrachis sp.

Hymenoptera

Apidae

Apis mellifera

Amegilla acraensis

Amegilla sp.1

Amegilla sp.2

Amegilla sp.3

Braunsapis foveata

Ceratina sp.1

Crossisaspidia chandleri

Dactylurina staudingerii

Meliponula ferruginea

Xylocopa inconstans

Xylocopa olivacea

Halictidae

Lasioglossum nairobicum

Lipotriches notabilis

Thrinchostoma sjostedti

Megachilidae

Chalicodoma cinta cinta

Chalicodoma rufipes

Megachile torrida

Formicidae

Camponotus flavomarginatus

Vespidae

Belonogaster juncea

(sp.)

FR: Fruiting Rate; MNS/F: Mean Number of Seeds per Fruit; PNS (%): Percentage of Normal Seeds; sp: undetermined species.

Supplementary 4. Yields according to plant families repeated in the Sahelo-Sudanian agro-ecological zone of Cameroon.

Plants	Years and references	Months	Flora Entomofauna			Impact of flower-feeding insects on the fruit and seed yields of the plants studied
						Yields			Numerical contributions (%)
						FR (%)	MNS/F	PNS (%)	FR	MNS/F	PNS
Fabaceae family
			Order	Family	Genus, species, sub-species
Phaseolus vulgaris	Douka & Tchuenguem, 2013	June - August	Hymenoptera	Apidae	Apis mellifera adansonii	52.31	5.10	94.19	35.57	20.32	7.72
					Amegilla sp.
					Thyrus sp.
					Xylocopa sp.
				Formicidae	Polyrachis sp.
				Halictidae	Lipotriches collaris
					Macronomia vulpina
				Megachilidae	Chalicodoma sp.
					Megachile sp.
				Sphecidae	Philanthus triangulum
				Vespidae	Synagris cornuta
			Diptera	Calliphoridae	(sp. 1)
					(sp. 2)
			Coleoptera	Scarabeidae	(sp. 1)
					(sp. 2)
			Hemiptera	Coreidae	Anoplocnemis curvipes
			Lepidoptera	Acraeidae	Acraea acerata
				Pieridae	Catopsilia florella
				Pieridae	(sp. 1)
			Orthoptera		(1 sp.)
					(2 sp.)
			Dictyoptera	Mantodae	(sp. 1)
			Nevroptera		(sp. 1)
					(sp. 2)
Glycine max	Tchuenguem & Dounia, 2014	August - September	Hymenoptera	Apidae	Apis mellifera adansonii	92.37	3.53	86.88	5.86	31.29	22.85
					Amegilla sp. 1
					Xylocopa sp. 1
				Halictidae	Macronomia vulpina
					Lipotriches collaris
				Megachilidae	Chalicodoma sp.1
					Megachile sp. 1
					Megachile sp. 2
				Formicidae	Polyrachis sp. 1
				Vespidae	Synagris cornuta
					(1 sp.)
				Sphecidae	Philanthus triangulum
					(1 sp.)
			Lepidoptera	Pieridae	Catopsilia florella
					(sp. 1)
					(sp. 2)
				Nymphalidae	(1 sp.)
				Acraeidae	Acraea acerata
			Diptera	Muscidae	Musca domestica
				Drosophilidae	Drosophila sp. 1
				Syrphidae	(1 sp.)
				Calliphoridae	(1 sp.)
			Hemiptera	Coreidae	Anoplocnemis curvipes
				Pyrrhocoridae	Dysdercus voelkeri
			Orthroptera		(sp. 1)
					(sp. 2)
			Nevroptera		(sp. 1)
					(sp. 2)
Vigna unguiculata	Djonwangwé et al., 2017	August - November	Hymenoptera	Megachilidae	Megachile eurymera	53	9.99	8.99	16.98	10.71	13.35
				Apidae	Xylocopa inconstans
					Xylocopa olivacea
				Vespidae	(1 sp.)
			Lepidoptera	Hesperiidae	Pelopidas mathias
				Pieridae	Hemiargus hanno
					Eurema senegalensis
					Vanessa cardui
					Danaus chrysippus
					(1 sp.)
				Erebidae	Utetheisa pulchella
			Hemiptera	Lygaeidae	(1 sp.)
			Diptera	Muscidae	(1 sp.)
			Coleoptera	Meloidae	Hycleus senegalensis
Malvaceae Family
			Order	Family	Genus, species, sub-species
Gossypium hirsutum	Dounia & Tchuenguem, 2013	August - October	Hymenoptera	Apidae	Apis mellifera adansonii	92.5	31.92	91.45	30.29	40.83	22.58
					Allodape sp.
					Amegilla sp. 1
					Amegilla sp. 2
					Thyrus sp.
					Xylocopa sp. 1
					Xylocopa sp. 2
				Formicidae	Polyrachis sp. 1
				Halictidae	Lipotriches collaris
					Macronomia vulpina
				Megachilidae	Chalicodoma sp. 1
					Chalicodoma sp. 2
					Creightonella sp.
					Megachile sp. 1
					Megachile sp. 2
					Megachile sp. 3
				Sphecidae	Philanthus triangulum
					(1 sp.)
				Vespidae	Synagris cornuta
					(1 sp.)
				Eumenidae	Delta sp.
			Diptera	Calliphoridae	(1 sp.)
					(2 sp.)
				Stratiomyiidae	Hermetia sp.
				Syrphidae	(1 sp.)
			Coleoptera	Scarabeidae	(1 sp.)
					(2 sp.)
				Meloidae	Coryna sp.
			Hemiptera	Coreidae	Anoplocnemis curvipes
				Pyrrhocoridae	Dysdercus voelkeri
			Lepidoptera	Acraeidae	Acraea acerata
				Nymphalidae	(1 sp.)
				Pieridae	Catopsilia florella
				Pieridae	(1 sp)
				Pieridae	(2 sp)
			Orthroptera		(1 sp.)
					(2 sp.)
			Dythioptera	Mantodae	(sp)
			Nevroptera		(1 sp)
					(2 sp)
Gossypium hirsutum	Basga et al., 2019	June - November	Coleoptera	Meloidae	Coryna sp.	94.50	27.99	88.79	27.54	36.47	25.37
				Coccinelidae	Cheilomenes lunata
			Diptera	Muscidae	Musca domestica
				Syrphidae	1 sp.
			Heteroptera	Pentatomidae	1 sp.
			Hymenoptera	Apidae	Apis mellifera
				Formicidae	Camponotus sp.
					Myrmicaria opaciventris
				Halictidae	Macronomia vulpina
					Lasioglossum sp.
					Crocisaspidia chandleri
					1 sp.
				Megachilidae	Chalicodoma kamerunensis
					1 sp.
				Sphecidae	Philanthus triangulum
					Sceliphron spirifex
				Vespidae	Belonogaster juncea
					(1 sp.)
			Lepidoptera	Nymphalidae	Charaxes jasius
			Orthoptera	Acridae	1 sp.
					Tettigonia viridissima
Gossypium hirsutum	Adamou et al., 2020a	June - October (2018) & July - October (2019)	Coleoptera	Coccinellidae	Cheilomenes lunata	90.41	24.65	92.28	14.12	21.65	11.33
				Meloidae	Coryna sp.
			Diptera	Calliphoridae	(1 sp.)
				Muscidae	Musca domestica
				Syrphidae	Episyrphus sp.
					(1 sp.)
			Heteroptera	Pentatomidae	(1 sp.)
			Hymenoptera	Apidae	Amegilla sp.
					Apis mellifera
				Formicidae	Camponotus sp.
					Myrmicaria opaciventris
				Halictidae	Macronomia vulpina
				Vespidae	Belonogaster juncea
					(1 sp. 1)
					(1 sp. 2)
			Lepidoptera	Nymphalidae	(1 sp.)
				Pieridae	Eurema sp.
					Papilio demodocus
					(1 sp.)
			Orthoptera	Acrididae	Tettigonia viridissima
					(1 sp.)
Euphorbiaceae Family
			Order	Family	Genus, species, sub-species
Ricinus communis	Douka & Tchuenguem, 2014	September - November	Diptera	Muscidae	Musca domestica	96	2.81	94.13	90.63	94.66	85.05
				Calliphoridae	(1 sp.)
			Hymenoptera	Formicidae	Polyrachis sp.
				Vespidae	Synagris cornuta
					Delta sp.
			Hemiptera	Coreidae	Anoplocnemis curvipes
			Lepidoptera	Lycaenidae	(1 sp.)
				Pieridae	Eurema sp.
				Acraeidae	Acraea acerata
				Pieridae	Catopsilia florella
			Orthoptera		(sp. 1)
					(sp. 2)
			Odonate	Zygoptera	(1 sp.)

FR: Fruiting Rate; MNS/F: Mean Number of Seeds per Fruit; PNS (%): Percentage of Normal Seeds; sp: undetermined species.

Supplementary 5. Yields according to repeated plant families in the West Highlands agro-ecological zone of Cameroon.

Plants	Years and references	Months	Flora Entomofauna			Impact of flower-feeding insects on the fruit and seed yields of the plants studied
						Yields			Numerical contributions (%)
						FR (%)	MNS/F	PNS (%)	FR	MNS/F	PNS
Solanaceae Family
			Order	Family	Genus, species, sub-species
Physalis micrantha	Otiobo et al., 2015b	June - July	Diptera	Drosophilidae	Drosophila sp.	65.40	367	98.64	6.63	6.38	0.69
				Muscidae	Musca domestica
				Syrphidae	Paragus borbonicus
			Hymenoptera	Apidae	Amegilla sp.
					Apis mellifera adansonii
					Braunsapis sp.
					Ceratina sp.
					Dactylurina staudingeri
					Lasioglossum atricum
					Melipoluna erythra
				Formicidae	Camponotus flavomarginatus
				Megachilidae	Megachile sp.
			Lepidoptera	Acraeidae	Acraea acerata

FR: Fruiting Rate; MNS/F: Mean Number of Seeds per Fruit; PNS (%): Percentage of Normal Seeds; sp: undetermined species.

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.

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