Oviposition Behavior Research Articles

Cut to Disarm Plant Defence: A Unique Oviposition Behaviour in Rhynchites foveipennis (Coleoptera: Attelabidae)

Female weevils of the family Attelabidae (Coleoptera: Curculionoidea) possess a unique behaviour of partially cutting the branches connecting egg-bearing organs of their host plants during oviposition. However, the consequence of such behaviour remains unclear. Using Rhynchites foveipennis and its host pear (Pyrus pyrifolia), the present study tested the hypothesis that the oviposition behaviour could disarm the host plants' defence. We compared the survival rates, growth rates, and performance of eggs and larvae under two conditions: (1) the fruit stems were naturally damaged by the females before and after oviposition, and (2) the fruit stems were artificially protected from the females. When fruit stems were protected from female damage, the survival rates of eggs and larvae were only 21.3-32.6%, respectively; and the larval weight was 3.2-4.1 mg 30 days after laying eggs. When the fruit stems were damaged, the survival rates of eggs and larvae reached 86.1-94.0%, respectively; and the larval weight reached 73.0-74.9 mg 30 days after laying eggs. The contents of tannin and flavonoids in the pears did not change significantly along with the oviposition and larval feeding, but weevil eggs were crushed and killed by the callus in the pears. Once the stunted larvae in branch-growing pears were moved into the picked-off ones, the growth and development recovered. The findings indicate that the oviposition behaviour can significantly increase the survival of the offspring. Our study suggested that the oviposition behaviour of attelabid weevils is a strategy to overcome plant defence.

Inhibition of alternative oxidase disrupts the development and oviposition of Biomphalaria glabrata snails

BackgroundBiomphalaria glabrata is one of the main intermediate hosts of Schistosoma mansoni, the most widespread species of Schistosoma. Our previous studies proved that alternative oxidase (AOX), the terminal oxidase in the mitochondrial respiratory chain, widely exists in several species of intermediate host snails of Schistosoma. Meanwhile, inhibition of AOX activity in Oncomelania hupensis snails could dramatically enhance the molluscicidal effect of niclosamide. As a hermaphroditic aquatic mollusc, the high fecundity and population density of B. glabrata increase the difficulty of snail control, which is one of the critical strategies for schistosomiasis elimination. The present study aimed to investigate the possible role of AOX in the development and fecundity of B. glabrata snail, which could be manipulated more manageable than other species of intermediate host snails of Schistosoma.MethodsThe dynamic expression of the AOX gene was investigated in different developmental stages and tissues of B. glabrata, with morphological change and oviposition behaviour observed from juvenile to adult snails. Furtherly, dsRNA-mediated knockdown of BgAOX mRNA and the AOX protein activity inhibiting was performed to investigate the effect of AOX on the development and oviposition of snails.ResultsThe BgAOX gene expression profile is highly related to the development from late juveniles to adults, especially to the reproductive system of snails, with a positive correlation of 0.975 between egg production and BgAOX relative expression in ovotestis of snails. The inhibition of BgAOX at the transcriptional level and AOX activity could efficiently inhibit snail growth. However, the interference at the BgAOX protein activity level led to more severe tissue damage and more significant inhibition of oviposition than at the transcriptional level. This inhibition of growth and oviposition decreased gradually with the increase in the snail size.ConclusionsThe inhibition of AOX could efficiently disrupt the development and oviposition of B. glabrata snails, and the intervention targeting AOX at the juvenile stage is more effective for snails. This investigation explored the role of AOX in the growth and development of snails. It would benefit snail control in the future by providing a potential target while using molluscicides more efficiently.Graphical abstract

Two odorant receptors regulate 1-octen-3-ol induced oviposition behavior in the oriental fruit fly

The oriental fruit fly Bactrocera dorsalis (Hendel) is a notorious pest of fruit crops. Gravid females locate suitable oviposition sites by detecting host plant volatiles. Here, we demonstrate that 1-octen-3-ol, a volatile from mango, guides the oviposition behavior of female flies. Two odorant receptors (BdorOR7a-6 and BdorOR13a) are identified as key receptors for 1-octen-3-ol perception by qPCR analysis, heterologous expression in Xenopus laevis oocytes and HEK 293 cells followed by in vitro binding assays, as well as CRISPR/Cas9 genome editing in B. dorsalis. Molecular docking and site-directed mutagenesis are used to determine major binding sites for 1-octen-3-ol. Our results demonstrate the potential of 1-octen-3-ol to attract gravid females and molecular mechanism of its perception in B. dorsalis. BdorOR7a-6 and BdorOR13a can therefore be used as molecular targets for the development of female attractants. Furthermore, our site-directed mutagenesis data will facilitate the chemical engineering of 1-octen-3-ol to generate more efficient attractants.

Effects of ejaculate size on remating, attractiveness, and oviposition in females of the sweetpotato weevil, Cylas formicarius

AbstractIn many insect species, female remating is triggered by the reduction in male ejaculates stored by females, including sperm and/or seminal fluids transferred during mating. Although females of the sweetpotato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae) are not monogamous, they are slow to remate. We investigated whether male age and mating history, which affect ejaculate size, influence female reproduction in this weevil. We prepared two female groups with different ejaculate sizes (small or large). Females that mated with young (10‐day‐old) virgin males with small ejaculates remated earlier than those that mated with older (30‐ or 50‐day‐old) virgin males with large ejaculates. The 6‐day fecundity did not differ between females that attracted males and those that did not, suggesting that most females with less ejaculate can lay eggs. Given that the number of sperm in the spermathecae of females that attracted males was smaller than that in females that did not attract males, we hypothesize that less ejaculate might enhance a female's attractiveness to males. Interestingly, 20% of females that laid no eggs on the last day observed (day 6) contained >1000 sperm in the spermatheca suggesting that sperm depletion alone did not suppress oviposition behavior. In conclusion, females of this weevil that had received small ejaculates were likely to be attractive to males, resulting in female remating, but cessation of oviposition is not due to sperm depletion alone; instead, it is likely a response to a decrease in the level of seminal fluids.

Mating and Oviposition Behaviour of Brinjal Shoot And Fruit Borer, Leucinodes Orbonalis Guenee

Mating and oviposition behaviour of brinjal shoot and fruit borer (BSFB), Leucinodes orbonalis Guenee (Lepidoptera:Pyralidae) were carried out in the laboratory on brinjal plants maintaining the temperature (20-250C) and relative humidity (80-85%). The moths were found active at night for mating and oviposition. Mating usually occurred at late night but a few moths were found to continue mating up to 8.0 hour of the day. Maximum moths completed mating between 4.00 to 6.00 hour of the day. Mating period ranged from 28-50 minutes. Mating occurred in first and second night of the adult emergence. Majority of the moths (90.80%) were found to mate in the first night and the rest went for mating in the following night. Oviposition always occurred at night. Females were always found to oviposit at night with an average 86.62% oviposition during the first half of the night. Again 60% egg deposition of first half of the night occurred during 20.00 to 22.00 hours. A female laid 241.50 eggs in an average of 2.70 days of oviposition. The egg laying pattern indicates that the egg laying continued for a maximum of 4 days showing a decreasing pattern of deposition with the increase of age. About 50% of the total eggs were deposited on the first day. The BSFB females preferred brinjal leaves for oviposition. Distribution of the eggs on the upper and lower surfaces of the leaves was found 1:2.74. Females showed higher preference for upper canopy of the brinjal plant as oviposition site.
 Bangladesh J. Agril. Res. 46(3): 285-296, September 2021

Distance-based Decision-making in Oviposition by Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) on Low- and No-gluten Flours.

The increasing popularity of low- and no-gluten flours as wheat flour alternatives has driven the need to understand risks of insect pest infestation in these products. Previous research using no-choice bioassays found that the red flour beetle, Tribolium castaneum Herbst can oviposit and develop on a range of alternative flours; here we test T. castaneum preference by assessing attraction in a wind tunnel assay and oviposition preference in both small- and large-scale choice assays between alternative and wheat flour. Some flours such as buckwheat, teff, millet, rice, and rye elicit similar responses as wheat flour for both attraction and oviposition. Other flours such as cassava and oat were not preferred for either oviposition or attraction behaviors. Flours like sorghum and amaranth, had mixed preferences for oviposition, with decreased oviposition in the small arena but not the large arena. Comparisons to published developmental success rates of T. castnaeum on these dietsindicate that females can choose diets on which they have high developmental success, such as buckwheat or teff, and avoid flours like cassava where developmental success is low. However, mismatch of oviposition preference and developmental success also occurs, in flours such as rice and amaranth. These results suggest the red flour beetle has limited ability to make adaptive food selections for egg laying. Further analysis of the chemical and physical properties associated with preferred and nonpreferred flours can provide information on cues associated with egg laying as well as how these cues could be exploited in pest management programs.

Conserved Odorant Receptor, EcorOR4, Mediates Attraction of Mated Female Eupeodes corollae to 1-Octen-3-ol

Odorant receptors (ORs) in insects are crucial for the detection of chemical signals. However, the functions of the conserved OR genes among insect species are rarely studied. In this study, we analyzed a well-conserved OR clade in Diptera insects and cloned a gene from this clade, EcorOR4, in the hoverfly Eupeodes corollae. Real-time quantitative PCR showed that EcorOR4 was highly expressed in the antennae and upregulated in the mated females, and in vitro functional characterization showed that EcorOR4 was narrowly tuned to 1-octen-3-ol. Electroantennogram assays revealed that the antennal response of mated females to 1-octen-3-ol was significantly higher than that of mated males, but no significant differences were observed between male and female virgins. Finally, a Y-tube olfactometer bioassay showed that 1-octen-3-ol is an attractant for only mated female E. corollae adults. These results demonstrate that EcorOR4 is involved in the detection of 1-octen-3-ol and that this compound may affect the host-finding and oviposition behavior in female E. corollae.

Influence of Senegalia macrostachya seed availability on Caryedon furcatus (Anton & Delobel) oviposition behaviour and its larvae survival

Senegalia macrostachya is a wild legume whose seeds are highly prized by the Burkinabe population. Unfortunately, they are severely depreciated during storage by the main pest Caryedon furcatus. However, very few studies have looked at the impact of the amount of S. macrostachya seeds on major biological parameters such as egg laying and development of C. furcatus. These data could contribute to better control of this pest. The aim of the study was to evaluate the impact of the quantity of S. macrostachya seeds on the egg laying behaviour of C. furcatus and on the ability of the larvae to weave their cocoons. Pairs of C. furcatus up to 24 hours old were placed separately with Petri dishes containing 5, 10, 20, 50, 100 and 200 seeds of S. macrostachya in four replicates per treatment. The seeds were renewed daily until the females died. After egg laying, the seeds were incubated until adult emergence. Our results showed that the rate of egg-bearing seeds increased significantly from 77.60% when the female had 5 seeds to 100% when she had 100 seeds. Similarly, the rate of larvae that were able to weave their cocoons increased significantly with the number of seeds. The variation in the amount of seeds and the number of pairs of C. furcatus has a strong impact on the behaviour and development of C. furcatus. The results suggest the need to control C. furcatus on S. macrostachya especially in case of mass storage for the benefit of the consumers.

Interspecific differences in microhabitat use expose insects to contrasting thermal mortality

AbstractEcotones linking open and forested habitats contain multiple microhabitats with varying vegetal structures and microclimatic regimes. Ecotones host many insect species whose development is intimately linked to the microclimatic conditions where they grow (e.g., the leaves of their host plants and the surrounding air). Yet microclimatic heterogeneity at these fine scales and its effects on insects remain poorly quantified for most species. Here we studied how interspecific differences in the use of microhabitats across ecotones lead to contrasting thermal exposure and survival costs between two closely‐related butterflies (Pieris napiandP. rapae). We first assessed whether butterflies selected different microhabitats to oviposit and quantified the thermal conditions at the microhabitat and foliar scales. We also assessed concurrent changes in the quality and availability of host plants. Finally, we quantified larval time of death under different experimental temperatures (thermal death time [TDT] curves) to predict their thermal mortality considering both the intensity and the duration of the microclimatic heat challenges in the field. We identified six processes determining larval thermal exposure at fine scales associated with butterfly oviposition behavior, canopy shading, and heat and water fluxes at the soil and foliar levels. Leaves in open microhabitats could reach temperatures 3–10°C warmer than the surrounding air while more closed microhabitats presented more buffered and homogeneous temperatures. Interspecific differences in microhabitat use matched the TDT curves and the thermal mortality in the field. Open microhabitats posed acute heat challenges that were better withstood by the thermotolerant butterfly,P. rapae, where the species mainly laid their eggs. Despite being more thermosensitive,P. napiwas predicted to present higher survivals thanP. rapaedue to the thermal buffering provided by their selected microhabitats. However, its offspring could be more vulnerable to host‐plant scarcity during summer drought periods. Overall, the different interaction of the butterflies with microclimatic and host‐plant variation emerging at fine scales and their different thermal sensitivity posed them contrasting heat and resource challenges. Our results contribute to setting a new framework that predicts insect vulnerability to climate change based on their thermal sensitivity and the intensity, duration, and accumulation of their heat exposure.

Life history and behavior of Tamarixia triozae parasitizing the tomato-potato psyllid, Bactericera cockerelli

Tamarixia triozae is an important primary parasitoid of the tomato-potato psyllid, Bactericera cockerelli, a serious cosmopolitan pest of solanaceous crops. However, without better information about its life history and behavior, it will be difficult to use this parasitoid in effective biological control programs. We carried out a series of experiments to characterize its parasitism, adult feeding, and oviposition behaviors and its sex allocation in response to different life stages of its host, and their fitness consequences. We show that T. triozae females fed on all host instars with a preference for mid-aged ones, and preferred to parasitize later instars, thus inflicting mortality on all instars simultaneously. Host feeding and parasitism peaked during the first week of female life and declined markedly after two weeks. Parasitoids allocated more fertilized eggs to older and larger nymphs, and superparasitism declined with increasing host density. The oviposition rate of fertilized eggs peaked when females were four to five days old, with > 90 % of daughters produced during the first half of adult life. The body size and egg loads of progeny increased with increasing host instar at parasitism, demonstrating a positive relationship between the host size and offspring fitness.

Responses of macroinvertebrate functional trait structure to river damming: From within-river to basin-scale patterns

Revealing how aquatic organisms respond to dam impacts is essential for river biomonitoring and management. Traditional examinations of dam impacts on macroinvertebrate assemblages were frequently conducted within single rivers (i.e., between upstream vs. downstream locations) and based on taxonomic identities but have rarely been expanded to level of entire basins (i.e., between dammed vs. undammed rivers) and from a functional trait perspective. Here, we evaluated the effects of dams on macroinvertebrate assemblages at both the within-river and basin scales using functional traits in two comparable tropical tributaries of the Lancang-Mekong River. At different scales, maximum body size, functional feeding groups (FFG), voltinism and occurrence in drift respond significantly to dam impact. Armoring categories varied significantly between downstream sites and upstream sites, and oviposition behavior, habits and adult life span significantly differed between rivers. The key traits at the within-river scale resembled to those at the between-river scale, suggesting that within-river trait variation could further shape functional trait structure at the basin scale in dammed rivers. Furthermore, water nutrients and habitat quality induced by dams showed the most important role in shaping trait structure, although trait-environment relationships varied between the two different scales. In addition, the trait-environment relationships were stronger in the dry season than in the wet season, suggesting a more important role of environmental filtering processes in the dry season compared with the wet season. This study highlights the utility of the trait-based approach to diagnose the effects of damming and emphasizes the importance of spatial scale to examine dam impacts in riverine systems.

Circular RNA ame_circ_2015 Function as microRNA Sponges in Regulating Egg-Laying of Honeybees (Apis mellifera).

Honeybees (Apis mellifera) are critical to maintaining ecological balance and are important pollinators. The oviposition behavior in honeybees is important and complex. Circular RNAs (circRNAs) are found to form circRNA-miRNA crosstalk and play important roles in reproduction processes. Here, dual luciferase reporter was used to confirm the crosstalk between ame_circ_2015 and ame_miR-14-3p. Functional experiments in vitro and in vivo were performed to investigate the biological functions of ame_circ_2015 in egg-laying of queens. The results showed that ame_circ_2015 directly target ame_miR-14-3p, and the expression of ame_circ_2015 was negatively correlated with ame_miR-14-3p expression. Overexpression results showed that ame_circ_2015 promoted the number of eggs laid and knockdown of ame_circ_2015 suppressed the number of eggs laid. It demonstrates that up-regulated ame_circ_2015 promotes the number of eggs laid by sponging ame_miR-14-3p. The study will provide information towards a better understanding of circRNA-miRNA crosstalk in egg-laying in honeybees.

Case closed – Wrappings and encasement delays and reduces fly presence on body parts

Homicide, particularly where a body has been concealed, is uniquely challenging for investigators to estimate the time of occurrence due to the methods employed by perpetrators to hide the body or its constituent parts from detection. The regularity of necrophagous insect lifecycles to determine minimum post-mortem interval (minPMI) is widely employed but remains an unreliable technique if used without a clear understanding of the factors that affect insect access and oviposition behaviour to concealed remains.The purpose of this study was to investigate the effect of wrapping body parts on fly colonisation and implications for minPMI calculations. Field studies were carried out using four treatments of pork (as surrogate body parts), in five replicates, one unwrapped, the other three wrapped in either a black plastic sack, a small-zipped wash bag (to simulate a suitcase), or a plastic sack further placed in a wash bag. Over a 48-h period all the methods of wrapping significantly disrupted the host-finding process of blowflies to dismembered carcasses, with a delay of initial contact and oviposition of 30+h (dependant on wrapping) and even more in wet conditions (48+ h). Egg numbers were also reduced by as much as 99.1% on wrapped samples compared to unwrapped. These new findings highlight the importance of applying adjustments to minPMI calculations when encountering wrapped remains. Advances in the accuracy of minPMI calculations will prevent the waste of valuable police time and resources and better focus the search for witnesses and suspects in homicide investigations.

Influence of Phaseolus vulgaris L. (Fabaceae: Fabales) varieties on oviposition behavior and susceptibility to infestation by Acanthoscelides obtectus Say (Coleoptera: Bruchidae)

Despite beans being a vital source of cheap protein, its yield is reduced mainly by diseases, field and storage pests. An effective and sustainable control option against storage insect pests could be improving the genetic resistance of the host plant in relation to the behaviour of the pest. A laboratory investigation was conducted to determine effects of bean varieties on oviposition behaviour and susceptibility to infestation by Acanthoscelides obtectus. The experiments evaluated oviposition site preference, number of eggs laid, and number of progeny and emergence holes of A. obtectus per bean variety. The number of progeny and duration in days taken by 50 % of progeny to emerge was determined and used to calculate susceptibility index. Seed harness index, thickness of testae and surface area of bean varieties were determined and related with susceptibility indices. Results indicated that the number of eggs laid, progeny, and emergence holes, duration taken by progeny to emerge, susceptibility indices, seed surface area and hardness were statistically different. Mwezi moja variety was the most preferred host for oviposition whereas Mwitemania was the least preferred. Beetles laid the highest (84.5) number of eggs in Mwezi moja and the least (41.9) in Mwitemania. Number of progeny of A. obtectus emerging were the highest in Mwezi moja (73.7) and the least (36) in Mwitemania. Beetles took the shortest (36.75 days) period to emerge from Mwezi moja and the longest (38.63days) period from Mwitemania. Mwezi moja was the most susceptible variety to attack by A. obtectus with a susceptibility index of 7.43 and Mwitemania was the least susceptible with an index of 6.51. Nyayo had the highest (0.019) seed hardness index and Mwezi moja and Canadian wonder had the least (0.012) hardness index. Mwezi moja had the largest (278mm) surface area whereas Mwitemania had the lowest (171mm) surface area.

What Defines a Host? Oviposition Behavior and Larval Performance of Spodoptera frugiperda (Lepidoptera: Noctuidae) on Five Putative Host Plants

When an invasive species first breaches quarantine and establishes in yet another country, it invariably causes consternation for growers, in part because of incomplete understanding of the plants that are at risk. The Fall Armyworm, Spodoptera frugiperda (J.E. Smith) is the most recent example in Australia. The number of plants that this polyphagous noctuid is reported to attack is vast, including many crop species. Consequently, initial reactions from grower industry groups that perceived themselves at risk were to demand emergency use of insecticides. Yet the field evidence suggests that many crops might not be at risk and since S. frugiperda arrived in Australia, maize crops have suffered most damage, followed by sorghum. We question the accuracy of some of the claims of reported host plants of S. frugiperda and report experiments that compared oviposition behavior, neonate silking behavior, and larval performance on five crops: the known hosts maize and sorghum, and the putative hosts cotton, peanut, and pigeon pea. Maize ranked highest in all preference and performance measures, followed by sorghum and peanut, with pigeon pea and cotton ranking lowest. Although S. frugiperda can survive, develop, and pupate on the crop species we examined, cotton and pigeon pea are not preferred by the pest in either the larval or adult stages. We suggest that before a plant is listed as a host for a given insect that the evidence should be fully reported and carefully evaluated. Collecting an immature insect from a plant does not make that plant a host!

FEEDING DETERRENCE INDEX OF Momordica cymbalaria FENZL EX HOOK AGAINST COMMON CUT WORM, Spodoptera litura FABRICIUS

Plant secondary metabolites exhibit a wide range of biological activity and may act as feeding and oviposition deterrents, repellents, fumigants, and behavior modifiers. Fruits and tubers of Momordica cymbalaria Hook (Fenzl.) possess anti-ovulatory and abortifacient properties that could be exploited in the management of insect pests. Hence, the feeding deterrent activity of M. cymbalaria leaf, peel (fruit skin), seed and tuber solvent extract against Spodoptera litura Fabr. was studied. Different concentrations of acetone extract of leaf from 0.3% to 0.8%, performed better in deterring S. litura larval feeding. Peel acetone extract showed a strong feeding deterrence (94.83% leaf area protection over the absolute control) at 0.9% concentration followed by medium deterrence at 0.8, 0.7, and 0.6% concentrations (85.62, 77.90, and 67.08 % protection respectively). The hexane seed extract was comparatively oilier and had a distinct rancid smell noticeable in the higher concentrations (0.8, 0.9, and 1%). Tubers did not exhibit any significant leaf area protection below 0.2% concentration. However, 1% tuber acetone extract showed 99.36 percent protection. The effective concentrations of leaf acetone extract for 50 and 95% deterrence were 0.27and 0.84 percent respectively. The effective concentrations of other plant parts were ranked as follows; Seeds>Peels>Tubers.

Chitosan and Essential Oils Combined for Beef Meat Protection against the Oviposition of Calliphora vomitoria, Water Loss, Lipid Peroxidation, and Colour Changes.

Meat production has a higher economic and ecological impact than other commodities. The reduction in meat loss and waste throughout the whole supply chain is a demanding challenge. In recent years, the interest in the food-grade polysaccharide chitosan (CH) and essential oils (EOs) employed as allies in meat protection has increased. In this work, we selected five EOs obtained from plants traditionally used as spices, and after their chemical characterisation, a trained panel of expert sensorial analysts determined that, among them, Laurus nobilis (Lauraceae) and Piper nigrum (Piperaceae) EOs were the most suitable to season meat. Therefore, the effect of CH, the L. nobilis and P. nigrum EOs, and EOs-enriched CH solutions on meat was tested to assess how they deter the oviposition behaviour of the blowfly Calliphora vomitoria (Diptera: Calliphoridae) and against water loss, lipid peroxidation, and colour changes. All the applied treatments, compared to the control, did not accelerate meat dehydration but increased colour lightness, an attractive feature for consumers, and discouraged the blowfly's oviposition. In particular, the P. nigrum EO-enriched CH was the most active in repelling C. vomitoria without negatively affecting the organoleptic qualities and shelf-life of meat.

Fitness landscapes reveal context-dependent benefits of oviposition behavior.

Resource choice behavior has enormous fitness consequences and can drive niche expansion. However, individual behavioral choices are often mediated by context, determined by past experience. Do such context-dependent behaviors reflect maladaptive variation or are they locally adaptive? Using Tribolium castaneum (the red flour beetle), we demonstrate that context-dependent oviposition behavior reflects distinct, context-specific local fitness peaks. We measured offspring fitness to generate fitness landscapes as a function of all possible oviposition behaviors (i.e., combinations of fecundity and resource preference) in a habitat containing optimal and suboptimal resource patches. We did this by experimentally manipulating egg allocation across patches, which allowed us to assess behaviors not typically observed in the laboratory. We found that females from different age and competition contexts exhibit distinct behaviors which optimize different fitness components, linked in a tradeoff. With prior exposure to strong competition and increasing age, females produce few but fast-developing offspring that are advantageous under high resource competition. In contrast, young naïve females produce significantly more (but slower developing) offspring, which is beneficial under weak competition. Systematically mapping complete context-dependent fitness landscapes is thus critical to infer behavioral optimality and offers predictive power in novel contexts.

Oviposition behaviour in Drosophila melanogaster: Genetic and behavioural decoupling between oviposition acceptance and preference for natural fruits.

In phytophagous insects, oviposition behaviour is an important component of habitat selection and, given the multiplicity of genetic and environmental factors affecting its expression, is defined as a complex character resulting from the sum of interdependent traits. Here, we study two components of egg-laying behaviour: oviposition acceptance (OA) and oviposition preference (OP) in Drosophila melanogaster using three natural fruits as resources (grape, tomato and orange) by means of no-choice and two-choice experiments, respectively. This experimental design allowed us to show that the results obtained in two-choice assays (OP) cannot be accounted for by those resulting from no-choice assays (OA). Since the genomes of all lines used are completely sequenced, we perform a genome-wide association study to identify and characterize the genetic underpinnings of these oviposition behaviour traits. The analyses revealed different candidate genes affecting natural genetic variation of both OA and OP traits. Moreover, our results suggest behavioural and genetic decoupling between OA and OP and that egg-laying behaviour is plastic and context-dependent. Such independence in the genetic architectures of OA and OP variation may influence different aspects of oviposition behaviour, including plasticity, canalization, host shift and maintenance of genetic variability, which contributes to the adoption of adaptive strategies during habitat selection.

Influence of pigeon pea (Cajanus cajan) on oviposition behaviour of Diceraeus melacanthus stink bug, an important pest of soybean and maize crops in South America

Influence of pigeon pea (Cajanus cajan) on oviposition behaviour of Diceraeus melacanthus stink bug, an important pest of soybean and maize crops in South America