- Networking in Homestead Area, Noakhali, Bangladesh

Sanjay Saha Sonet1 Fairuj Humaira1 Md.Shahin1 Fariha Binte Amin1 Md Nazrul Islam1 Pijush Kanti Jhan2 Sadia Sultana3 Md. Monzer Hossain Sarker1 Mohammed Mahbubur kabir1

Abstract

Plants and play a crucial role for ecosystem function and process. Like Coastal forest areas other coastal villages area comprises rich amount of planted tree species including natural growing herbs, shrubs and climbers along with dependent vast insect community. No studies have been performed to understand in the field the relevance of the interaction between and the insects potentially feeding on them (at the community level) especially. The field work was performed in area of NSTU campus and surrounding homestead area, Noakhali, a coastal area of Bangladesh which comprises rich amount of planted trees including naturally growing herbs, shrubs and climbers which support a vast amount of insects. In this study, the interaction at the herbivores level was observed in summer season and winter season, and its overall status has been evaluated. Plots were taken randomly, and insects were collected from different plants and identified in laboratory by specialist. Ecological network was constructed to assess the interactions of insect with plants in this ecosystem. Total 40 species of plant representing 21 families and 15 different orders; and 34 insect species representing 24 families and 9 different orders. Most of them were from (9), Orthoptera (7) and Coleoptera (5) and fewer were from Hymenoptera (3), (3), Odonata (2), Diptera (1), Arenea (2), Blattedae (1). Out of these 34 insect species, 20 insect species found herbivorous. In total, 20 different herbivorous insects were collected from 19 different plants, revealing a total of 800 interactions and 246 links. The study area portrayed the situation where lower numbers of herbivorous species were dependent on higher number of plant species. The herbivorous species in there have number of choices and ample amount of food for surviving.

1. Department of Environmental Science and Disaster Management, Noakhali Science and Technology University, Noakhali-3814, Bangladesh 2. Department of Agriculture, Noakhali Science and Technology University, Noakhali-3814, Bangladesh 3. Department of Zoology, Noakhali Science and Technology University, Noakhali-3814, Bangladesh

Correspondence: Sanjay Saha Sonet, Lecturer, Department of Environmental Science and Disaster Management, Noakhali Science and Technology University, Noakhali-3814, Bangladesh. Email: [email protected] We found lower moderate niche overlap for herbivores (0.42) where herbivores shared their dependent plant species for food with other herbivore species lower to moderate quantity. Myzus persicae, Schistocerca gregaria, and Halymorpha halys (27, 25 and 24 respectively, degree) connected with highest number of plant species for their livelihood where Spilosoma sp., Opisina arenosell and Tetragonula Carbonira connected with least number of species (3, 4 and 6 respectively, degree).

Keywords: Bipartite network, Plant-insect, Biodiversity, Homestead area, Bangladesh.

Introduction

Interactions between plants and insects are considered to be one of the key drivers of ecosystem function and process. Insect plays an important role both as consumer of plants and contributors to the next higher trophic levels. They are important entity of the food web, links between plant production and production of other at higher trophic levels. True ecological complexity of plant– insect interactions also describes the context of global climate change and multiple biotic and abiotic stresses (Ryalls and colleagues 2015). To understand ecosystem function it is essential getting in depth knowledge on plant and insect interconnection.

Insects are the largest group of the kingdom, reaching more than 58 percent of the known global biodiversity (Foottit and Adler 2009). About 43 percent of all insects, from different taxonomic orders - almost all the Lepidoptera and Orthoptera, around 90% of Hemiptera and Thysanoptera, 35% of Coleoptera, 30% Diptera and 11% Hymenoptera - are considered to be phytophagous (Bernays and Chapman 1994). However, the rate of diminishing insects continuously becomes higher in last decade. It is important to identify them in their functional place and conserve those insect species.

Insects may largely influence the organization of plant communities and their patterns of species richness (Hulme 1996). Insects can interact with plants through two different ways: feeding on plant parts (leaf chewing, sap sucking, seed predation, gall inducing, leaf mining and feeding on fruits); or through pollination (Vamosi et al. 2006). In nature, it is common for some insects to be specialist on one particular plant (monophagous) or on its closely related species, while others feed on a wide range of plants (oligophagous) (Bernays and Chapman 1994). Insect herbivores have highly diverse life cycles and feeding behaviors. They establish close interactions with their plant hosts and suppress plant defense. The mechanisms of plant recognition of insect attack as well as downstream signaling and defence mechanisms, but broaden the subject by also

26 | Page introducing mechanisms by which insects recognize their hosts and overcome plant defences (Bruce 2015).

A network analysis between plants and insects in a specific area could be useful to address the insects host specificity and provide more information about their interaction, as suggested by Harrison and Rajakaruna (2011). It also might enable a deeper insight of that individual plant in a community, with the interaction with other neighbors’ and upper food web components and providing the sense of ecological evolution and adaptation (Dormann et al. 2014). Moreover, the community framework will allow us to work with the assemblages of herbivores in plant covers with different plant species compositions. Recently, Heleno et al. (2014) reviewed the progress and prospects of the network analysis in ecology as an innovative tool for getting better information and a more practical and better illustration of the plant-animal interaction.

Plant–insect interactions is an excellent example of the success of the modern approaches taken in advanced biology (e.g. Walling 2000; Berenbaum 2002; Kessler and Baldwin 2002; Dicke and Hilker 2003; Hartmann 2004). An ecological network can be considered as a representation of the biotic interactions between two or among more than two trophic levels in an ecosystem, in which species (nodes) are connected by pairwise interactions (links) (Pascual and Dunne 2005). The use of ecological networks in food webs is not limited to only describe networks based on species average data but also to explore the pattern of species level data, including by recognition of individual traits and behaviour at community level (Ings et al. 2009; Heleno et al. 2013).

Methodology

Study area This study has been conducted in Noakhali Science and Technology University campus and surrounding area which located in Sonapur (22° 47′ 36.18″ N, 91° 06′ 01.95″ E). The site of the study area is a part of a vast Char that stretches on the south to Char Jabbar, Char Bata, Char Wapda, Char Clark before it reaches the feebly flowing Bhulua river (BBS 1999). The average temperature of this district ranges from a maximum 34.3°c to a minimum 14.4°c. Average rainfall of the district throughout the year is 3302 mm.

Experimental setup The study site was sampled during the winter and summer season, 2019. The study plot was drawn in randomly only in vegetative area of the campus. In total, 20 plots (each plot 400 m2 in size) were selected for observation both in

27 | Page summer and winter season in same plot and sixty minutes (by 3 persons) was spent for random observation in every plot.

Within each plot, plants were selected arbitrarily and sampled to collect insects. Sampling was done either by using potters/tongs or by hand/net (for small plants/bushes), sweeping net (for big bushes/small trees) to collect the insect loads. All host plants were registered and identified in situ (the ones that could not be identified in situ were collected and identified in the laboratory). All the visits were done in sunny days, between 9.30 am to 2pm. All insects collected from each plant were immediately preserved in vials containing 96% alcohol and placed in refrigerated boxes for further identification. Insect identification was done in the laboratory to the lowest taxonomical level possible.

Species interaction network Ecological network is a practical tool that can allow one to check the individual plant interaction hypothesis of the species in a natural environment and provide a deeper insight of that particular plant within a community. Eventually, it can unravel this species fundamental role in its community.

Data analysis All the parameters in network level were calculated using statistical bipartite package v.2.04 for R (Dormann et al. 2014; R Development Core Team 2010).

Result and Discussion

A total of 34 insect species were collected during the visits, comprising 24 families and 9 Orders: 9 (27.27%) Hemiptera, 7(21.21%) Orthoptera, 5(15.15%) Coleoptera, 3 (9.09%) Lepidoptera, 3(9.09%) Hymenoptera, 2 (6.06 %) Odonata, 2 (6.06%) Araneae, 1(4.54%) Blattodea, 1(4.54%), 1(4.54%) Diptera.

40 different species of plants from 21 families were found to interact with herbivorous insects in the study site. Among all these plants, 26 (65%) of these plants were trees, 10 (25%) herbs, 2(5%) were vines and 1 (2.5%) perennial. Most abundant families were (6), Poaceae (5), Arecaceae (3), Cucurbitaceae (3) and Myrtaceae (2).

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ant ant code is in the

The The insect code is in the upper

);

).

Momordica Momordica charantia

longiareolata Culiseta

Figure Figure 1: Overall herbivores plant interaction network. The width bars represents the number of observed interactions. The pl lower side of the Bar and the first three letters from each species name (e.g. Momcha for for Cullon (e.g. name species each from letters three first the and Bar of the side

29 | Page Out of 34 insect species 20 species were found herbivorous, and these herbivorous insects were selected for further subsequent analysis. Our study result found a total of 20 different herbivorous insects were collected from 40 different plants, revealing a total of 584 interactions and 246 links (see Figure 1).

In total 20 different herbivorous insects were collected from 40 different plants, revealing a total of 584 interactions and 246 links (see Figure 1). High Alatalo interaction evenness (0.77) was found in this community indicated that abundant amount of similar number of interactions found among the herbivores and plants in this community. The study area portrayed the situation where lower numbers of herbivorous species were dependent on higher number of plant species (web asymmetry = 0.333). The herbivorous species in there have higher number of choices and ample amount of food for surviving.

The herbivorous loads taken by different plants were lower in number (niche overlap 0.30). In this community herbivores showed low specialization (see Table 1). Most of the herbivores have more than one choice for their food. In fact, these herbivores were comparatively generalist in nature and have taken several plant species in consideration to feed on. This study results found herbivores were aggregate in nature and found several individuals of one species found in together (V ration 6.36 >1).

The studied network revealed that on average 11 insects and plants species interact with each other. In this community no generalist herbivores found completely subset of previous generalist herbivores resulted in lowest value for nestedness (31.82) and weighted nestedness (0.41) (see Figure 2).

On an average every plant species provided food for approximately 9 herbivore species. Very few specialized herbivorous species showed lower interaction with other plant species and showing lower matched up with other species. Alternatively, interaction strength of asymmetry, another index of this network, showed specialist herbivores established very low interaction strength with different plant species (-0.04).

We found lower moderate niche overlap for herbivores (0.42) where herbivores shared their dependent plant species for food with other herbivore species lower to moderate quantity. So, lower togetherness index value of plants community and dependent herbivore also indicated the same scenario. The majority of available insect species increase their number only if there is availability of their different specific food availability. In the study result these herbivores showed lower randomness that means herbivores have showed a level of species association.

30 | Page In total 20 different herbivorous insect interacted with 40 different plants for food resources. Among the connection of plants and their dependent herbivores found very low (0.31). Average per species connectance of this community was also found low (0.25) and confirmed the message conveyed by the low connectance index value (see Table 1).

In total, this community structured with 1 compartment along with every species linked with approximately 4 species. The average shared plants number of herbivore in that community was approximately 5 plants species.

Table 1: Network analysis parameter descriptors

Pure network indices Values Group level network indices Values Linkage density 11.10 Niche overlap (HL) 0.42 Link per species 4.10 Niche overlap (LL) 0.30 Connectance 0.31 Togetherness (HL) 0.22 Weighted Connectance 0.19 Togetherness (LL) 0.19 Web asymmetry -0.33 Robustness (HL) 084 Shannon diversity 5.29 Robustness (LL) 0.92 Nestedness 31.82 Partner diversity (HL) 2.50 Weighted nestedness 0.41 Partner diversity (LL) 2.00 Interaction evenness 0.80 Generality (HL) 13.53 Alatalo Interaction evenness 0.77 Vulnerability (LL) 8.68 B Fisher alpha 160.13 Mean number of shared partners (HL) 4.92 Interaction strength asymmetry -0.04 Mean number of shared partners (LL) 2.35 Specialization asymmetry 0.14 C score (HL) 0.36 NODF 15.77 C score (LL) 0.37 Weighted NODF 25.71 V ratio (HL) 6.36 H2 0.22 V ratio (LL) 4.07 Cluster coefficient 0.25 Extinction slope (HL) 5.38 Number of compartment 1 Extinction slope (LL) 11.63

In this community, plants and their dependent herbivores showed lower interactions evenness (0.80) along with lower Alatalo interaction evenness (0.77); and in field this study found plants and herbivores interacted sparsely. In total, 40 plant species found in this fragment community. There is lower possibility of affected by extinction of plants species in this community in compare to their dependent herbivore unless there is any kind of anthropogenic activity. Interaction strength asymmetry indicated that the strength of plants interaction with herbivore is higher than the herbivore interaction with plants as higher number of plant species along with lower amount of dependent herbivore species found in this community.

The study area portrayed the situation where lower numbers of herbivorous species were dependent on higher number of plant species (web asymmetry = -0.333). The herbivorous species in there have higher number of

31 | Page choices and ample amount of food for surviving. Very few specialized herbivorous species showed lower interaction with other plant species and showing lower matched up with other species.

Figure 2: Nestedness feature of plant and herbivores interactions

32 | Page Species level network Description

Myzus persicae, Schistocerca gregaria, and Halymorpha halys (27, 25 and 24 respectively, degree) connected with highest number of plant species for their livelihood where Spilosoma sp., Opisina arenosell and Tetragonula Carbonira connected with least number of species (3, 4 and 6 respectively, degree). We also found higher normalized degree value for Myzus persicae, Schistocerca gregaria, and Halymorpha halys (0.68, 0.63 and 0.60 respectively) and least value for Spilosoma sp, Opisina arenosell and Tetragonula Carbonira (0.08, 0.10 and 0.15 respectively). Due to having connected with higher number of plant species, these Myzus persicae, Schistocerca gregaria, and Halymorpha halys were gained higher species strength in this artificial community (6.91, 4.23 and 3.94 respectively) and they tried to pull the herbivores connections strongly (0.22, 0.12 and 0.13 respectively, interaction push and pull). On the other hand, those least connected herbivores gained highest nested value (1.00, 0.95 and 0.89 respectively) as they connected with least number of plant species which were subsets of those species which herbivores had higher connection along with lowest nested rank (such as Myzus persicae nested value = 0). These least connected herbivores (Spilosoma sp., Opisina arenosell and Tetragonula Carbonira) showed as specialist in nature (PDI = 0.95, 0.92 and 0.92 respectively) and have highest species specificity (Species specificity = 0.56, 0.48 and 0.42 respectively) along with higher node specialization (1.26, 1.47 and 1.05 respectively).

Overall Myzus persicae, Schistocerca gregaria, and Halymorpha halys species were showed generality in nature (13.53). However, Myzus persicae, Schistocerca gregaria, and Halymorpha halys showed higher fisher alpha (160.63) as it connected with higher number of diversified plants species for their livelihood along with highest diversified partner and also gained the highest number of effective partners.

In previous analysis in NSTU campus which was analyzed in winter season. A network analysis for the herbivorous insect interaction was considering in the presence of herbivores in host plant. The high majority of the herbivores were observed from tree and herb. A higher abundance of herbivorous insects were found in some plants. Like Vachellia nilotica, Magnifera indica probably due to the fact that these plants offer a higher amount of resources to the herbivores. Though it was winter season the insects has more interaction with the trees and most of the orders were from Lepidoptera Like butterflies, Hawk , Cabbage butterfly etc.

The study area can easily be characterized by having a sparsely vegetated area, as it is already attributed by the dominant of tree species and

33 | Page resulted in most of the interactions found on tree, as they offer a higher amount of resources to the herbivores.

Conclusion

This results provided a foundation for further future work focused on the path ways for plant-insect interaction to higher trophic level and further impact on surrounding areas. Applying the network analysis by bipartite network included local to global importance indices analysis to describe the structure of plant insect network. A higher number of visits especially when all the plants have already bloomed could be considered for better result in further study.

References

Berenbaum, M. R. (2002) ‘Postgenomic chemical ecology: from genetic code to ecological interactions’, Journal of chemical ecology. Springer, 28(5), pp. 873–896. Bernays, E. A. and Chapman, R. E. (1994) ‘Behavior: the process of host-plant selection’, Host-plant selection by phytophagous insects. Springer, pp. 95–165. Bruce, T. J. A. et al. (2015) ‘The first crop plant genetically engineered to release an insect pheromone for defence’, Scientific reports. Nature Publishing Group, 5, p. 11183. Dicke, M. and Hilker, M. (2003) ‘Induced plant defences: from molecular biology to evolutionary ecology’, Basic and Applied Ecology. Elsevier, 4(1), pp. 3–14. Dormann, C. F., Fründ, J. and Gruber, B. (2014) ‘Package “bipartite”: visualising bipartite networks and calculating some (ecological) indices. R package, version 2.04’, See http://cran. r-project. org/web/packages/bipartite. Foottit, R. G. and Adler, P. H. (2018) ‘Insect biodiversity: science and society, volume II.’, Insect biodiversity: science and society, volume II. John Wiley & Sons. Hartmann, T. (2004) ‘Plant-derived secondary metabolites as defensive chemicals in herbivorous insects: a case study in chemical ecology’, Planta. Springer, 219(1), pp. 1–4. Heleno, R. et al. (2014) ‘Ecological networks: delving into the architecture of biodiversity’. The Royal Society. Heleno, R. H. et al. (2013) ‘Seed dispersal networks in the Galápagos and the consequences of alien plant invasions’, Proceedings of the Royal Society B: Biological Sciences. The Royal Society, 280(1750), p. 20122112. Ings, T. C. et al. (2009) ‘Ecological networks--beyond food webs.’, The Journal of animal ecology, 78(1), pp. 253–69. doi: 10.1111/j.1365-2656.2008.01460.x. Kessler, A. and Baldwin, I. T. (2002) ‘Plant responses to insect herbivory: the emerging molecular analysis’, Annual review of plant biology. Annual Reviews 4139 El Camino Way, PO Box 10139, Palo Alto, CA 94303-0139, USA, 53(1), pp. 299–328. Pascual, M. and Dunne, J. A. (2006) Ecological networks: linking structure to dynamics in food webs. Oxford University Press. Vamosi, J. C. et al. (2006) ‘Pollination decays in biodiversity hotspots’, Proceedings of the National Academy of Sciences. National Acad Sciences, 103(4), pp. 956–961. Walling, L. L. (2000) ‘The myriad plant responses to herbivores’, Journal of plant growth regulation. Springer, 19(2), pp. 195–216.

34 | Page Annex 1: List of Plant species Order Family Scientific name Plant code Local Name Plant status Alismatales Araceae Colocasia Colocasia esculenta colesc Kochu Herb Apiales Apiaceae Centilla Centilla asitica Cenasi Thankuni Herb Cocos Cocos nucifera Cocnuc Narikel Tree Arecaceae Phoenix Phoenix dactylifera Phodac Khejur Tree Arecales Areca Areca catechu Arecat shupari Tree Asteraceae Enhidra Enhidra fluctunas Enhflu Helencha Herb Tamarix dioica Tmadio Jhau Tree Luffa Luffa aegyptiaca Lufaeg Dhundul Tree Cucurbitales Cucurbitaceae Coccinia Coccinia grandis Cocgra Telakucha Herb, Climber Momordica Momordica charantia Momcha Korola Herb, Climber Acacia auriculiformi Acaaur Akashmoni Tree Tamarind Tamarind indica Tamind Tetul Tree Tamarix Tamarix dioica Tamdii Sirish gach Tree Fabaceae Dalbergia Dalbergia sissoo Dalsis Sisso Tree Albizia lebbeck Albleb Koroi Tree Albizia Albizia procera Albpro Shilkoroi Tree Acacia Acacia acuminata Acaacu jam Tree Rubiaceae Neolamarckia Neolamarckia cadamba Neocad Kadam Tree Gentianales Apocynaceae Plumeria Plumeria alba Plualb Kath champa Tree Malvales Malvaceae Bombax Bombax ceiba Bomcei Simul Tree Terminalia arjuna Terarj Arjun Tree Combretaceae Terminalia Terminalia catappa Tercat Kaju Badam Tree Myrtales Syzygium malaqeens Syzmal Jamrul Tree Syzygium Myrtsceae Syzygium cumini Syzcum Java Plum Tree Psidium Psidium guajava Psigua Peyara Tree Saccharum Saccharum spontaneum Sacspo Kashful Herb Cynodon Cynodon dactylon Cyndac Durba grass Herb Poales Poaceae Oplismenus Oplismenus burmannii Oplpoa Basket grass Herb Festuca Festuca arundinacea Fesaru Grass Herb Brachiaria Brachiaria mutica Bramut Para grass Herb Polypodiales Pteridaceae Acrostichum Acrostichum aureum Acraur Pteris Fern Rhamnaceae Ziziphus Ziziphus mauritiana Zizmau Boroi Tree Rosales Moraceae Ficus Ficus carica Ficcar Tinfal Tree Mangifera Mangifera indica Manind Mango Tree Anacardiaceae Spondias Spondias mombin Spomom Amra Tree Sapindales Azadirachta Azadirachta indica Azaind Neem Tree Meliaceae Swietenia Swietenia macrophylla Swimac Mehogany Tree Solanaceae Solanum Solanum melongena Solmel Begun Herb Solanales Convolvulaceae Ipomoea Ipomoea aquatica Ipoaqu Palon shak Herb Zingiberales Musaceae Musa Musa sapientum Mussap kola Perennial

Annex 2: List of Insect species Order Family Genus Species Insect code Local name Insect status Theridiidae Achaearanea Achaearanea tepidariorum Achtep Spider carnivores Araneae Agelenidae Agelenopsis Agelenopsis actuosa gertsch Ageact Grass spider carnivores Blattodea Ectobiidae Blattella Blattella germanica Blager German coackroach omnivores Buprestidae Buprestidae Buprestidae spp. Bup spp. Metallic beetle omnivores Carabidae Carabus Carabus monilis Carmon Ground beetle omnivores Coleoptera Lucanidae Chondropyga Chondropyga dorsalis Chodor Cowboy beetle carnivores Coccinellidae Micraspis Micraspis discolor Micdis lady bird beetle carnivores Monolepta Monolepta signata Monsig Leaf hopper herbivores Diptera Culicidae Culiseta Culiseta longiareolata Cullon Mosquto herbivores Cicadellidae Cofana Cofana spectra Cofspe Leaf beetle herbivores Pentatomidae Halymorpha Halymorpha halys Halhal Brown stink bug herbivores Alydidae Leptocorisa Leptocorisa oratorius Lepora Rice bug herbivores Aphididae Lipaphis Lipery herbivores Hemiptera Aphididae Melanacanthus Melanacanthus margineguttatus Melmar Bean bug herbivores Aphididae Myzus Myzus persicae Myzper Green peach aphid herbivores Pentatomidae Nezara Nezara viridula Nezvir Green stink bug herbivores Aphrophoridae Philaenus Philaenus spumarius Phispu Frog hopper herbivores

35 | Page Order Family Genus Species Insect code Local name Insect status Membracidae Stictopelta Stictopelta spp. Sti spp. Tree hopper herbivores Formicidae Formica Formica rufa Forruf Red ant omnivores Hymenoptera Formicidae Lasius Lasius niger Lasnig Black garden ant omnivores Apidae Tetragonula Tetragonula Carbonira Tetcar Honey bee herbivores Pieridae Delias Delias eucharis Deleuc butterfly herbivores Black head cater Lepidoptera Cryptophasidae Opisina Opisina arenosell Opiare herbivores piller Erebidae Spilosoma Spilosoma spp. Spi spp. Cater pillar herbivores Libellilidae Neurothemis Neurothemis tullia Neutul Dragonfly carnivores Odonata Coengrionoidae Pyrrhosoma Pyrrhosoma nymphula pyrnym Damselfly carnivores Grillidae Acheta Acheta domesticus Achdom House cricket omnivores Pyrgomorphidae Atractomprpha Atractomorpha crenulata Atrcre Green grasshopper herbivores Grillidae Gryllus Gryllus spp Gry spp. Field cricket omnivores Short horned Acrididae Oxya Oxya spp. Oxy spp1 herbivores Orthoptera grasshopper Long horned Acrididae Oxya Oxya spp. oxy spp2 herbivores grasshopper Acrididae Oxya Oxya chinensis Oxychi Brown grasshopper herbivores Acrididae Schistocera Schistocerca gregaria Schgre Locust herbivores

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