Ecological Entomology

Elevation gradients pose challenges for flying insects due to temperature and air density shifts, impacting their thermoregulation, flight abilities and subsequently species distribution patterns. Geometrid moths are a model group for studying these traits among insects. This study examines how trait-patterns and niche differentiation of Geometrid moth assemblages change with elevation. Investigating 697 specimens of 120 Geometrid moth species, I assessed species diversity, turnover, and various traits related to body size and flight capabilities along a 1500m elevation span in the western Himalayas. Results indicate a decline in species diversity along the elevational gradients, accompanied by consistent turnover from lower to higher elevations. Despite this pattern, elevation did not significantly influence morphological traits related to thermal sensitivity (body size) and flight capability (wing loading and manoeuvrability) at the assemblage level in Geometrid moths. Furthermore, there was no significant niche differentiation among species across elevations. This supports the argument that species with similar ecological roles persist through turnover, maintaining consistency in trait values across assemblages. These findings from the paleotropics align with patterns observed in Geometrid moths across neotropical and temperate regions, highlighting the importance of trait-based approaches in understanding species responses to environmental changes. Summary StatementThis study examines how Geometrid moth assemblages in the western Himalayas respond to elevational gradients, revealing consistent turnover, stable traits, and no significant niche differentiation, emphasizing trait-based species adaptation

Known parasitoids of ants include species from several families of flies, wasps, strepsipterans, nematodes, and mites. Curiously, while myrmecophily is heavily biased towards Coleoptera, one of the most diverse and speciose insect orders, no beetles specialized as parasitoids of ants have been recorded, although the parasitoid habit has evolved at least 13 times within this order. Here we report on observations that strongly suggest that a checkered beetle species behaves as a parasitoid of ant brood. A total of 146 colonies or part of colonies of three species of the Ectatomma ruidum species complex (E. ruidum sp. 2, 3, 4) were excavated in several sites along the Pacific coastal plains of Oaxaca, Mexico, during three collecting campaigns (2015-2017). Overall, 11060 adults, 5795 cocoons and 2185 larvae were examined. Upon dissection, four intact cocoons contained ant prepupae/pupae parasitized by characteristic campodeiform beetle larvae (prognathous head, three pairs of segmented legs on thorax, no prolegs, body with sparse but long pubescence), and a fifth cocoon presented a round exit hole. An active, pink-colored larva, emerged from a cocoon in 2015, was reared to the adult stage and could be identified as Phyllobaenus obscurus (Gorham) (Cleridae). Second and third instar larvae were found inside intact cocoons of two species: E. ruidum sp. 3 and sp. 4. The prevalence of parasitism is extremely low: less than 0.6% of cocoons available in each Ectatomma host populations. Predatory during both adult and larval stages, checkered beetles are broadly known as predators of wood-boring and cone-boring beetles, and some species are facultative parasitoids of solitary bees or wasps or, very rarely, specialized in predating social insects. We assert that the novel discovery of clerid-ant brood parasitoidism within the subterranean host colony deviates yet further from any known clerid adaptation to date.

Burying beetles of the genus Nicrophorus have become a model for studying the evolution of complex parental care in a laboratory. Nicrophorus species depend on small vertebrate carcasses to breed, which they process and provision to their begging offspring. However, vertebrate carcasses are highly sought after by a wide variety of species and so competition is expected to be critical to the evolution of parental care. Despite this, the competitive environment for Nicrophorus is rarely characterized in the wild and remains a missing factor in laboratory studies. Here, we performed a systematic sampling of Nicrophorus orbicollis living near the southern extent of their range at Whitehall Forest in Clarke County, Georgia, USA. We determined the density of N. orbicollis and other necrophilous species that may affect the availability of this breeding resource through interference or exploitation competition. In addition, we characterize body size, a key trait involved in competitive ability, for all Nicrophorus species at Whitehall Forest throughout the season. Finally, we compare our findings to other published natural history data for Nicrophorines. We document a significantly longer active season than was observed twenty years previously at Whitehall Forest for both N. orbicollis and Nicrophorus tomentosus, potentially due to climate change. As expected, the adult body size of N. orbicollis was larger than N. tomentosus, the only other Nicrophorus species that was captured in 2022 at Whitehall Forest. The other most prevalent interspecific insects captured included species in the families Staphylinidae, Histeridae, Scarabaeidae, and Elateridae, which may act as competitors or predators of Nicrophorus eggs and larvae. Together, our results indicate significant variation in intra- and interspecific competition relative to populations within the N. orbicollis range. These findings suggest that the competitive environment varies extensively over space and time, which help to inform the role of ecology in the evolution of parental care in this species.

The phoretic mite assemblage of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae) has not been as thoroughly documented as that of some other ecologically and economically important bark beetle species. Phoretic mites can impact individual fitness and population dynamics of their hosts and documenting the mite assemblage associated with a bark beetle may provide information on their ecological and interactive roles. We caught Douglas-fir beetles over two summers in central British Columbia, Canada and sorted the associated mites into morphospecies. Representatives of the morphospecies were DNA barcoded (cytochrome oxidate I barcode region) which indicated at least nine distinct Operational Taxonomic Units (OTUs). There was a mean of 50.5 {+/-} 4.7 mites per beetle with both females and males carrying similar numbers of most mite species. However one OTU (Sarcoptiformes: Hemisarcoptidae) was found in substantially higher numbers than all other OTUs, and was always clustered in large aggregations in an anterior pocket on the sub-elytral surface. When B1 was removed from the mean, there were only 1.3 {+/-} 0.2 mites per beetle. The consistent high numbers of that OTU in conjunction with its consistent anatomical aggregation suggests an important interaction between that mite species and the Douglas-fir beetle.

Diapause induction and termination, which regulate seasonal insect life cycles, can be highly variable within and among populations because these traits are often genetically variable and sensitive to environmental fluctuations. Both types of variation may influence how insect populations respond plastically or evolutionarily to changing climates. In this study we assessed variability in the expression of reproductive diapause in spruce beetles (Dendroctonus rufipennis), a major forest pest whose life cycle timing is regulated by both a prepupal and adult reproductive diapause. Prepupal diapause is facultative and dependent on temperature in the field, whereas previous studies suggest that adult reproductive diapause is effectively obligate. We tested for variability in adult reproductive diapause termination within and between two populations of spruce bark beetle collected from sites in Colorado and Wyoming and reared under warm, summer-like conditions in the laboratory. We also sampled beetles from under tree bark during the fall and spring to estimate how reproductive diapause might terminate naturally in the field. We present evidence that though most beetles induce and do not terminate diapause under constant warm conditions, a small proportion of females from both populations developed mature ovaries and successfully reproduced under warm conditions in the lab. Previous studies have suggested that most beetles require exposure to relatively low temperatures for several weeks to months to terminate diapause in the lab. We found that most female beetles sampled in the field had mature ovaries relatively early in the fall, suggesting that exposure to transiently low temperatures in the field may rapidly terminate adult reproductive diapause. Thus, adult reproductive arrest may primarily act as a block to prevent offspring production prior to winter and appears unnecessary for survival overwinter. Overall, our data do not suggest that major shifts in spruce beetle life cycles as mediated by adult reproductive diapause are immediately imminent with changing climates but, if the variability that we observed is heritable, adult reproductive diapause may have some capacity to evolve in both populations. ** Note ** all figures/tables designated with S are supplemental figures/tables that will appear only in the supplement in the published version. They are provided here alongside the main figures/tables, in-line in the order that they appear in the text for convenience.

Predation is the key to understanding trophic interactions. Because of the brief and cryptic nature of predatory behavior, sentinel prey has been widely adopted as an indirect way to identify predators and understand trophic interactions. However, sentinel prey presents only static visual cues, potentially biasing toward visually oriented predators whilst ignoring those that require other sensory cues to forage. Despite this, the effectiveness of sentinel prey has rarely been tested. Here, we focused on the weaver ant, Oecophylla smaragdina, a keystone predator widespread in the Asian and Australian tropics. As this species has large eyes and is known to visually navigate in their arboreal habitats, we hypothesized that they rely on visual cues to forage and that their predatory behavior will be captured by caterpillar-shaped sentinel prey. Ants were collected as colonies, and preference trials on baits were conducted using combinations of olfactory and static visual cues including the caterpillar shape. Surprisingly, O. smaragdina showed little or no preference for baits in the absence of olfactory cues and did not differentiate the shapes of baits regardless of the presence of olfactory cues. Our results indicate that O. smaragdina is likely to make predatory decisions based primarily on olfactory cues, while visual cues might be used for other behaviors. Furthermore, O. smaragdina is likely to be left out by the predation studies using sentinel prey models which is particularly alarming considering the dominant role of this species in the trophic interactions of tropical rainforests. Our study demonstrates that morphological characteristics, arboreal habitats, and visually oriented behavior do not necessarily suggest the use of static visual cues for predatory decisions. We suggest that sentinel prey models should not be used alone when the dominant predators are unlikely to use visual cues to make predatory decisions.

Age-specific patterns of nectar and pollen use by insect pollinators may reflect behavioral or physiological changes over the insects lifespan, and may also influence flower visitation rate. Studying Heliconius charithonia (Lepidoptera: Nymphalidae) and Psiguria umbrosa (Cucurbitaceae), we showed that honey-water (as a nectar substitute) intake increases over the first ten to twelve days of females life, while decreasing over the same age period for males, when individuals were fed ad libitum. Intake then remains stable at least through 28 days of age. Mean intake is higher for females than for males, and is not significantly affected by body size. Intake patterns for honey-water and pollen did not change with age in a similar manner. Pollen feeding increased significantly with age for both sexes, with females showing a two week delay in the increase when studied in a free-flying greenhouse population with competition for pollen. Under both ad libitum and pollen competition conditions, females collected more pollen than did males. Body size did not significantly affect the amount of pollen collected for either sex. Within each sex, butterflies with ad libitum pollen collected more pollen than those in a free-flying greenhouse population with more restricted pollen availability. These results suggest that two resources obtained from the same source, pollen and nectar, are not treated identically by the insect pollinator, and that the demography of the insect population may affect flower visitation rates in some cases. Further, foraging patterns for pollen and nectar are likely driven by physiological demand for different resource types.

While the Japanese rhinoceros beetle Trypoxylus dichotomus typically feeds on the sap of the oak Quercus acutissima and the crape myrtle Lagerstroemia subcostata during the night, it exhibits feeding activity both during the day and night when it utilizes the ash tree Fraxinus griffithii. However, the mechanisms underlying the variations in temporal activity patterns remain unknown. We compared feeding rates (measured as body mass increments) and sap exudation rates among F. griffithii, Q. acutissima, and L. subcostata. We found that beetles feeding on L. subcostata and Q. acutissima exhibited significantly higher feeding rates than those feeding on F. griffithii. No significant differences in feeding rates were observed between L. subcostata and Q. acutissima. The sap exudation rate was significantly higher for Q. acutissima than for F. griffithii. However, there were no significant differences in the sap exudation rates between F. griffithii and L. subcostata or between Q. acutissima and L. subcostata. These findings suggest that lower feeding rates on F. griffithii prolong the feeding duration, resulting in daytime activity. While the low sap exudation in L. subcostata seems inconsistent with high feeding rates on this host, this apparent contradiction could be related to the extended duration of sap exudation.

AimBiotic interactions are an important factor structuring ecological communities but data scarcity limits our understanding of the impact of their response to climate and land use changes on communities. We studied the impact of a change in species assemblage on biotic interactions in a community of closely-related butterflies. Specifically, we examined the impact of the recent range expansion of Araschnia levana on the resident species, with a particular focus on natural enemies, parasitoids, shared with other butterfly species in the assemblage. LocationSweden. Time periodTwo years (2017-2018). Major taxa studiedNettle-feeding butterflies (Aglais urticae, Aglais io, Araschnia levana, and Vanessa atalanta) and their parasitoids. MethodsWe assessed parasitism in 6777 butterfly larvae sampled in the field from 19 sites distributed along a 500 km latitudinal gradient, and every two weeks throughout species reproductive seasons. We identified the parasitoid complex of each butterfly species and their overlap, and analysed how parasitism rates were affected by species assemblage, variations in abundance, time, and the arrival of A. levana. ResultsParasitoids caused high mortality, with substantial overlap across the four host species. The composition of the host community influenced parasitism rates and this effect was specific to each species. In particular, the rate of parasitism in resident species was comparatively higher at sites where A. levana has been established for longer. Main conclusionsParasitoid pressure is a significant source of mortality in the nettle-feeding butterfly community studied. Variations in butterfly species assemblages are associated with substantial variations in rates of parasitism. This is likely to affect the population dynamics of their butterfly host species, and, potentially, the larger number of species with which they interact.

O_LISeveral polyphagous moths are severe crop pests. Diet breadth patterns and mechanisms among polyphagous insects provide an excellent system to study ecological and evolutionary processes in herbivores, driving dietary specialization. However, studies of diet breadth on more than a handful of crops are scarce. C_LIO_LIHere, we estimated the diet breadth in two species of lepidopteran herbivores from the genus Spodoptera: S. littoralis (SL), with host range including both mono- and dicotyledonous plants and S. frugiperda (SF) Corn strain, primarily adapted to different grass species. C_LIO_LILarval performance on 23 crop and wild plant species from 17 families from terrestrial and wetland habitats was compared to an artificial diet in no-choice feeding bioassays. SL survived and performed better on most tested plants, particularly on the family level, except on two monocot plants (maize and leek), where SF performed well. There were five wild non-host plants where both generalists failed to survive. Nutrition indices assay corroborates the findings on a subset of plants. C_LIO_LIIn a subset of plants, larval feeding preference correlated partly, and larval attraction correlated well with larval performance. Female oviposition choice showed a weak correlation with larval performance. This weak correlation implies that these traits are decoupled, and other factors are crucial for female host plant selection. C_LIO_LIDuring larval dispersal greenhouse experiments, SL and SF larvae strongly tended to migrate onto their suitable host plants, indicating that this is one factor that modulates female host plant selection. C_LIO_LIIn summary, SL has a broader diet breath compared to SF, surviving on wild plants with no previous exposure. The present study provides the first comprehensive data on the diet breadth of two range-expanding and highly invasive polyphagous herbivores. C_LI

Coexistence among Neotropical insectivorous bats (IB) that share roosts, foraging areas, and prey likely relies on processes promoting trophic niche divergence. We examined the diet and activity times of three coexisting IB species (Molossus molossus, Neoeptesicus furinalis, and Myotis nigricans) in Venezuelan rice fields in Northwestern Llanos to assess dietary and temporal overlap. Using published sources, we categorized prey by hardness and flight speed, bats by bite force and functional group, and examined the relationships among these variables. IB species showed differences in prey composition, type, and activity timing. As expected from its fast flight and strong bite, M. molossus diet consisted primarily of fast-flying, highly sclerotized insects, with activity times peaking significantly earlier than in the other two bat species. In contrast, M. nigricans and N. furinalis had diets consisting primarily of slower-flying prey and showed high temporal overlap in activity, although with different peak foraging times. Notably, N. furinaliss stronger bite may have enabled it to exploit more sclerotized prey than M. nigricans, despite similar flight capabilities--indicating that prey hardness helps reduce dietary overlap. These findings suggest that fine-scale trophic niche partitioning, enhanced by the rich insect fauna of rice fields, facilitates the coexistence of these ecomorphologically distinct IB species. Flexibilidad trofica favorece la coexistencia de tres especies de murcielagos cazadores aereos en cultivos de arroz de Venezuela. Teaser TextWe simultaneously identified prey items in feces and measured the activity times of three aerial-hawking bat species in Neotropical rice fields. We then explored the relationships between these variables and the functional traits of both prey and predators, confirming that coexistence might be facilitated by highly productive environments. RESUMENLa coexistencia entre murcielagos insectivoros (MI) neotropicales que comparten refugios, areas de forrajeo y presas probablemente depende de procesos que promueven la divergencia del nicho trofico. Examinamos la dieta y los tiempos de actividad de tres especies coexistentes de MI (Molossus molossus, Neoeptesicus furinalis y Myotis nigricans) en arrozales de los Llanos Noroccidentales de Venezuela para evaluar superposicion dietaria y temporal. Utilizando publicaciones, categorizamos a las presas segun su dureza y velocidad de vuelo, a los murcielagos segun su fuerza de mordida y grupo funcional, y examinamos las relaciones entre estas variables. Las especies de MI mostraron diferencias en la composicion, tipo de presas y tiempo de actividad. Como se esperaba por su vuelo rapido y mordida fuerte, la dieta de M. molossus consistio principalmente en insectos de vuelo rapido y esclerotizacion alta, con tiempos de actividad que alcanzaron un maximo significativamente antes que en las otras dos especies de murcielagos. En contraste, M. nigricans and N. furinalis tuvieron dietas que consistieron principalmente en presas de vuelo lento que mostraron una alta superposicion temporal en la actividad, aunque con distintos tiempos de forrajeo maximo. Cabe destacar que la mordida mas fuerte de N. furinalis pudo haberle permitido explotar presas mas esclerotizadas que M. nigricans, a pesar de sus capacidades de vuelo similares, lo que indica que la dureza de las presas ayuda a reducir la superposicion dietaria. Estos hallazgos sugieren que una particion fina del nicho trofico, facilitada por la rica fauna de insectos en los cultivos de arroz, promueve la coexistencia de estas especies de MI ecomorfologicamente distintas. Palabras clavecultivos, humedales artificiales, metabarcoding, murcielagos insectivoros, tiempo de actividad.

Fruit set, berry size, and berry weight were assessed for pollination by the solitary bee Osmia lignaria (Say) in caged rabbiteye blueberries (Vaccinium ashei Reade, Ericales : Ericaceae), and compared to that of uncaged rabbiteye blueberries which were pollinated largely by honey bees (Apis mellifera L). O. linaria produced berries that were 1.6mm larger in diameter and 0.45g heavier than uncaged blueberries. Fruit set was 40% higher in uncaged blueberries. This suggests that Osmia bees can produce larger and heavier berry fruit, but O. lignaria may be less efficient at blueberry pollination as compared to A. mellifera under field cage conditions.Competing Interest StatementThe authors have declared no competing interest.View Full Text

High trait variability among insects reflects a combination of intra- and inter-phenotype variations. Our aim was to assess if the trait distribution of body measurements can be more significantly influenced by sex (intraspecific variance) or by species (interspecific variance). To achieve this, we collected in Namibia tettigoniids belonging to two congeneric species of armoured ground crickets: Acanthoplus discoidalis (a significant pest in African croplands) and the long-legged Acanthoplus longipes. We measured in the field the total body length, the maximal pronotal width and length, and the femur and tibia lengths of the hind legs in 106 adults. We also derived the body mass from length and width values of the sampled specimens. No significant differences emerged in the two species by sex. A discriminant analysis clearly shows that at species level the locomotory traits as captured by tibia and femur lengths and the size traits as captured by body and pronotal lengths account for 99% of the total variance and clearly separate this pest from its congeneric species. In essence, it is not primarily the body size that differentiates the two species, but rather the pronotum and hind leg larger sizes of A. longipes. Different eco-ethological requirements, like the peculiarity of the calling song and the movements within the vegetation (and the consequently needed energy), independently force these functional traits.

Sarracenia insectivorous plants show a diversity of visual features in their pitchers but their perception by insects and their role in attraction, have received little attention. They also vary in prey composition, with some species trapping more flying Hymenoptera, such as bees. To test the hypothesis of a link between visual signal variability and prey segregation ability, and to identify which signal could attract flying Hymenoptera, we characterised, the colour patterns of 32 pitchers belonging to four taxa, modelled their perception by flying Hymenoptera, and examined the prey they trapped. The pitchers of the four taxa differed in colour patterns, with notably two long-leaved taxa displaying clear areoles, which contrasted strongly in colour and brightness with the vegetative background and with other pitcher areas in the eyes of flying Hymenoptera. These taxa trapped high proportion of flying hymenoptera. This suggests that contrasting areoles may act as a visual lure for flying Hymenoptera, making plants particularly visible to these insects. Prey capture also differed according to pitcher stage, morphology, season and visual characteristics. Further studies on prey visitation are needed to better understand the link between prey capture and attraction feature.

Plant fitness is shaped by interactions with insect mutualists and antagonists. Vegetative (leaf) herbivory often results in increased allocation of resources to defense in order to deter further damage. This allocation to defense can reduce floral or reproductive allocation. Reductions in floral allocation can have negative effects on pollinator attraction and therefore decrease plant fitness. However, defense-induced changes in reproductive tissues may also be protective against antagonistic fruit-feeding insects (frugivores). This may have important implications for plant fitness when plants experience multiple types of insect damage, but the potential protective effect of herbivory against frugivory is not well-understood. In this study, we tested the prediction that herbivory mediates interactions between plants and their antagonistic frugivores. In the greenhouse, we manipulated vegetative induction in Physalis pubescens (Solanaceae) and measured the effects on plant fitness via changes in floral and fruit allocation, herbivore resistance in the next generation, and deterrence of an antagonistic frugivore (Chloridea virescens (Lepidoptera)). Vegetative induction in P. pubescens enhanced plant resistance to Chloridea virescens frugivores with minimal negative effects on plant reproductive traits. Vegetative induction reduced C. virescens larval growth rate on fruits. Chloridea virescens also avoided induced plants for larval fruit feeding and oviposition. While leaf induction reduced flower size, induction did not negatively affect fruit size, seed set, or seed germination. Furthermore, offspring of induced plants showed increased resistance to Manduca sexta leaf herbivory. These findings indicate that herbivore-induced resistance may benefit plant fitness when plants are under simultaneous pressure from herbivores and frugivores.

Eusocial species differ in living conditions when compared to solitary species primarily due to the dense living conditions of genetically related individuals. Consequently, these crowded conditions can induce a high rate of pathogen transmission and pathogen susceptibility. To resist an epidemic, individuals rely on sets of behaviors, known as social immunity, to decrease pathogen transmission among nestmates. Alongside social immunity, ants have a pair of secretory metapleural glands (MG), thought to secrete antimicrobial compounds important for antisepsis, that are believed to be transferred among nestmates by social immune behaviors such as grooming. To investigate the effects of social immunity on pathogen resistance, we performed a series of experiments by inoculating acorn ants Temnothorax curvispinosus with a lethal spore concentration of the entomopathogenic fungus Metarhizium brunneum. After inoculation ant survival was monitored in two environments: solitary and in groups. Additionally, the MG role in pathogen resistance was evaluated for both solitary and grouped living ants, by sealing the MG prior to inoculations. Individuals within a group environment had a higher survival compared to those in a solitary environment, and individuals with sealed glands had significantly decreased survival than ants with non-sealed-MG in both solitary and social environments. We observed the lowest survival for solitary-sealed-MG individuals. Although sealing the MG reduced survival probability, sealing the MG did not remove the benefits of grouped living. We show here that social living plays a crucial role in pathogen resistance and that the MG has an important role in pathogen resistance of individual T. curvispinosus ants. Although important for an individuals pathogen resistance, our data show that the MG does not play a strong role in social immunity as previously believed. Overall, this study provides insights into mechanisms of social immunity and the role of MG in disease resistance.

O_LIRecent studies suggest that changes in leaf traits due to interactions between plants affect the resource utilisation and distribution of herbivores. However, this has not yet been confirmed experimentally. Here, we investigated the effects of phenotypic plasticity in leaf traits of Rumex obtusifolius (host plant) in response to the intra- and interspecific interaction on distribution of two leaf beetles, Gastrophysa atrocyanea (specialist herbivore) and Galerucella grisescens (generalist herbivore). C_LIO_LIWe investigated the local population density of R. obtusifolius plants and the presence of leaf beetles on the plants at five study sites. Leaf chemicals (condensed tannins and total phenolics) were compared between aggregated and solitary R. obtusifolius plants. To clarify the effects of the interaction environment of R. obtusifolius plants on their leaf traits and resource utilisation by leaf beetles, we conducted cultivation and preference experiments. Leaf chemicals (chlorophylls, organic acids, primary metabolites, condensed tannins and total phenolics) and preferences of adult leaf beetles were compared between intraspecific, interspecific plant interaction, or no-interaction treatments. Finally, we evaluated the effects of interaction between R. obtusifolius on leaf beetle distribution in mesocosm experiments. C_LIO_LIIn the field, the presence of the specialist leaf beetle, G. atrocyanea, was positively correlated with the local population density (rosette overlap ratio) of R. obtusifolius plants; however, no correlation was observed in the case of the generalist leaf beetle, G. grisescens. In the cultivation experiment, plants in the intraspecific interaction treatment increased their leaf contents of condensed tannins and total phenolics, and G. atrocyanea consumed more of these leaves than leaves in other treatments. Similar results were observed in the field. In the mesocosm experiment, larger numbers of G. atrocyanea were distributed on R. obtusifolius plants exposed to below-ground intraspecific interaction than on plants not exposed to intraspecific interaction. C_LIO_LIOur results provide experimental evidence that leaf-trait changes in response to intraspecific interaction between host plants influence specialist herbivore distribution. This highlights the need to integrate plant-plant interactions into our understanding of plant-animal interactions. C_LI

Mate choice is a fundamental aspect of sexual selection where the chooser chooses a courter by assessing a variety of traits that communicate potential fitness. However, the influence of interspecific interactions, such as symbiosis, on mate choice remains underexplored. We addressed this shortcoming with experiments on burying beetle Nicrophorus nepalensis and their interactions with phoretic mites Poecilochirus carabi. The mites can act either as mutualists or parasites depending on the presence of competitors and mite densities, thus potentially influencing mate choice. In a laboratory experiment, we presented female N. nepalensis with a range of natural mite densities: 0, 5, 10, or 20, with males carrying either 0 or 10 mites in an olfactory-based mate choice assay. Subsequently we allowed females to breed with their chosen male and all their mites before evaluating the fitness effects of the varying mite densities. We found that females across all mite densities had no preference for males with or without mites. In line with this, the mite densities had no effect on the brood size or the averaged larva mass. However, the mite densities per breeding cohort did positively affect the number of mite offspring. Our results suggest that mites act as benign passengers, not directly affecting mate choice or fitness.

Temperature profoundly impacts insect development, but plasticity of reproductive behaviors may mediate the impacts of temperature change on earlier life stages. Few studies have examined the potential for behavioral plasticity of adults to buffer developing offspring from warmer, more variable temperatures associated with climate change. We used a field manipulation to examine whether the dung beetle Phanaeus vindex alters breeding behaviors in response to climate change and whether adult behavioral shifts protect offspring from temperature increases. Dung beetles lay eggs inside brood balls made of dung that are buried underground for the entirety of offspring development. Depth of the brood ball impacts the temperatures offspring experience with consequences for beetle development. We placed females in either control or greenhouse treatments that simultaneously increased temperature mean and variance. We found that females produced smaller brood balls but buried them deeper in the greenhouse treatment, suggesting burial depth may come at a cost to brood ball size, which can impact offspring nutrition. Despite being buried deeper, brood balls from the greenhouse treatment experienced warmer mean temperatures but similar amplitudes of temperature fluctuation relative to the controls. Our findings suggest adult behaviors may buffer offspring from increased temperature variation due to climate change.

Landscape composition is central in shaping how pollinators utilise floral resources, yet its influence on foraging behaviour of co-occurring Asian honey bees remains underexplored. Resolving this gap is crucial to understand how closely-related, native and introduced species maintain foraging efficiency in rapidly changing environments. We investigated nectar preferences, sucrose responsiveness, and foraging task partitioning in three co-occurring honey bee species in India: Apis florea (native open-nesting), Apis cerana (native cavity-nesting), and Apis mellifera (introduced cavity-nesting), across forest, agricultural, and urban landscapes. Landscape type strongly influenced crop sugar concentrations of honey bees. While all species collected high-concentration nectar in forests, A. mellifera and A. cerana collected lower concentrations than A. florea in urban habitats. A. florea showed consistent preference for high-concentration nectar across landscapes. Complementing this, sucrose responsiveness assays revealed a lower responsiveness of A. florea compared to cavity-nesting species. Foraging task partitioning differed among species, but interestingly, also among landscapes. While A. cerana predominantly collected nectar, A. mellifera foraged equally for pollen, nectar and water, and A. florea shifted task allocation across landscapes. In conclusion, we provide the first comparative evidence that landscape composition and species characteristics jointly shape foraging preferences and organisation of foraging labour in Asian honey bees.