Abstract Offspring phenotypes are often influenced by maternal age at reproduction. However, the persistence of such effects across multiple generations remains poorly understood, especially in rare cases where offspring of older mothers exhibit enhanced performance. Using the predatory mite Amblyseius herbicolus , we experimentally tested whether maternal age at reproduction influences offspring life history across two generations under contrasting dietary conditions. We found that grandmaternal (F 0 ) and maternal (F 1 ) age affected offspring (F 2 ) developmental time and body size, but not hatching success, survival, or oviposition. The effect of maternal age on body size depended on grandmaternal age, suggesting that grandmaternal age mediates how mothers adjust offspring provisioning. Diet strongly influenced offspring traits but showed limited interaction with age effects. To our knowledge, this is the first study to demonstrate the persistence of an inverse Lansing effect across generations, whereby enhanced immature development is maintained without detectable trade-offs in reproduction or adult survival. These results identify maternal age as a key driver of transgenerational phenotypic variation, with important implications for population dynamics and responses to environmental change at the population level.

Males of many species compete with one another, allowing access to mating opportunities. During combat, contestants are constantly making decisions, e.g. to continue competing or retreat, based on the relative difference in resource holding potential (RHP) or some internal threshold. The outcome of these interactions is often based on the competitors RHP, which can be measured as the size of exaggerated traits (e.g. horns, mandibles, etc.) or overall body size. Competitive assessment models have been used to describe these behaviours and determine how animals assess their RHP and their opponent's RHP. This study looked at the contests of the Helm's stag beetle, Geodorcus helmsi, in a controlled laboratory environment. We found that larger males were more likely to win in an agonistic interaction and assumed that mandible length is a suitable proxy for RHP in this species. However, we did not find support for any assessment model being used in these contests. We also detail competitive behaviours of G. helmsi in a wild population for the first time. This study contributes to the research about the fighting behaviour in stag beetles and adds to the body of knowledge on New Zealand stag beetle behaviour, which has not been well studied.

While the consequences of flight loss in insects have attracted considerable attention, the underlying evolutionary drivers remain significantly less understood. Aotearoa New Zealand stands out as a region with a high proportion of flightless taxa in both highland and lowland areas. To investigate whether the most commonly accepted drivers of flight loss can be applied to New Zealand species from the beetle family Zopheridae, we conducted a correlated evolution analysis between flight loss and altitude, and flight loss and microhabitat type using a phylogeny. We reconstructed the ancestral state of hindwing presence / absence and analysed its effects on diversification rate. Our results revealed diversification rates are approximately 4.5 times faster with hindwind presence rather than absence, contrary to much previous research on insects. We also found New Zealand zopherids have lost their flight abilities multiple times, and this cannot be explained by any of the commonly accepted drivers of flight loss. Flight loss in New Zealand zopherids may be due to the unique biogeographic history as a continental island system.

Current approaches to assessing potential non-target risks associated with biological control agents are conservative, and they often rely on oviposition experiments conducted in quarantine laboratories. By their nature, such tests offer robust evidence of a parasitoid's ability to attack and develop in a host. However, they exclude many important chemical cues present in the natural environment, which play a key role in the ability of a parasitoid to search for and locate hosts. We conducted a series of experiments with Trissolcus basalis and Trissolcus oenone to better understand the chemical basis mediating differences in host-specificity between these parasitoids. First, we compared the searching behaviour of T. basalis and T. oenone in open arena arrestment bioassays contaminated with footprint compounds of Nezara viridula or Cuspicona simplex. Trissolcus basalis spent four times longer searching for N. viridula than C. simplex, while T. oenone spent four times longer searching for C. simplex than N. viridula. We then conducted competition experiments to assess factors important to determining the outcomes of extrinsic and intrinsic contests between these parasitoids when they are simultaneously exposed to C. simplex egg masses. Trissolcus oenone was the superior competitor in extrinsic and intrinsic contests. Finally, we recorded the antennal responses of T. basalis to egg extracts of N. viridula, to tentatively identify potential contact kairomones used by this parasitoid to recognise and accept hosts. We discuss our results in the context of combining behavioural and chemical ecological techniques for pre-release risk assessments of classical biological control agents.

The Lansing effect predicts a decline in offspring performance with increasing maternal age. Maternal age and diet can influence offspring development and fitness via maternal effects, but how these two factors interact remains poorly understood. We examined how maternal age at oviposition and dietary conditions affect offspring developmental plasticity in a thelytokous predatory mite ( Amblyseius herbicolus ). Mothers were provided either a restricted or abundant prey diet, and their offspring were exposed to varying prey availability and monitored for hatching success, survival to adulthood, developmental time, size at maturity, and prey consumption. We addressed two main questions: How does maternal age affect offspring developmental time and size at maturity and does maternal diet modify the effect of maternal age on offspring? Our results suggest an inverse Lansing effect. Offspring of older mothers showed increased survival and reduced prey consumption without any compromise in terms of size at maturity. Interactions were found between maternal diet and age on offspring prey consumption and developmental plasticity. Notably, offspring from older, diet-restricted mothers achieved the best overall performance during development. Our study demonstrates that maternal age and diet jointly shape offspring development, and highlights the importance of incorporating maternal age into studies of maternal effects and phenotypic plasticity. ### Competing Interest Statement The authors have declared no competing interest.

Antennal sensilla are fundamental to an insects sensory perception of its environment. In species where one sex produces pheromones for attracting mates, we can predict antennal and sensilla morphology to be sexually dimorphic. Prionoplus reticularis White (Prioninae; Cerambycidae; Coleoptera) is a large longhorn beetle exhibiting a scramble competition polygyny mating system with sexual dimorphism present in antennae length, suggesting chemical cues are of importance in male mate searching. The present study aims to investigate the antennal ultrastructure morphology and sexual dimorphism in this species using scanning electron microscopy. Various sensilla were identified only in males: sensilla filiformia, sensilla auricillica, wall pore hairs, and distal sensilla chaetica. These sensilla are known to have chemosensory and mechanosensory functions in other insect groups, suggesting these sensory organs play an important role in male mating strategies.

Traditionally, teaching entomology to undergraduate students has relied upon conventional laboratory-style practical classes-where students are taught how to collect, identify and curate specimens, as well as understand the form and function of key insect groups using unsophisticated but specialised equipment. Entomology educators had to promptly adapt their methods of teaching in response to the COVID-19 pandemic, which forced the online delivery of courses that often largely relied on face-to-face teaching. This imposed limitations on what could be effectively taught outside of a lab setting, although in many cases these were mitigated through online technology that introduced opportunities to support entomology students. Here, we assess the learning objectives of a range of current entomology courses taught namely in Australia, Aotearoa New Zealand, the United States and Europe. We found that practical hands-on skills, such as identification and curation, and understanding of insect morphology and diversity, often taught via lab activities, are common across many courses. Given the perceived tension between current moves to online educational delivery and these common practical learning objectives in entomology, we present a series of four activities that can be taught via online or distance approaches. These exercises can be used to effectively teach key concepts and skills such as identification, form and function and ecological research skills related to insects. We also discuss some challenges and benefits associated with the online delivery of entomology courses, emphasising a number of equity and accessibility benefits that online approaches might deliver.

Understanding variation in trait allometry and the drivers of variation in sexually selected traits is a major theme in evolutionary biology. The static allometries of sexually selected traits are often positive due to disproportional investment by large individuals into trait size. Comparative studies of weapon allometry are rare, and typically focus on variation along a single dimension (e.g. length), despite weapons often diverging dramatically in shape. Furthermore, studies predominantly focus on groups where weapons have evolved as novel structures (e.g. horns), despite most weapons arising from modifications of existing structures. We test the hypothesis that sexual selection drives variation in static allometry using a phylogenetic comparative approach with 59 brentine weevil species showing remarkable variation in trait exaggeration and sexual size dimorphism (SSD). Contrasting two dimensions of head size exaggeration (a sexually selected trait) and elytron length (a nonsexual trait), positive static allometry was common across both measures of male head size, but not females, and there was positive covariance between male head static allometry and SSD across species. Positive static allometry for male elytron length was less common, but did show positive covariance with SSD, possibly due to the function of wings as compensatory structures for bearing large weapons. Our findings support the hypothesis that sexual selection drives the evolution of allometries both within and among species, and that the modification of existing structures to be used as weapons does not limit the potential for positive static allometry.Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog.image

Parasitoid biological control agents rely heavily on olfaction to locate their hosts. Chemical cues associated with hosts and non-hosts are known to influence the expression of host preferences and host-specificity. A better understanding of how and why parasitoids attack some species and not others, based on volatile organic compounds associated with potential hosts, can provide key information on the parasitoid’s host preferences, which could be applied to pre-release risk assessments for classical biological control agents. Electrophysiological techniques such as electroantennography (EAG) and GC-EAD (gas chromatography coupled with electroantennographic detection) are widely used to identify bioactive semiochemicals. But the application of these techniques to understanding how chemical ecological cues mediate parasitoid host specificity has not been as thoroughly explored. We conducted GC-EAD and EAG studies to identify olfactory-active compounds associated with adult females of nine stink bug species from Aotearoa/New Zealand on the antennae of three closely related parasitoid species: Trissolcus japonicus Ashmead, a pre-emptively (= proactively) approved biocontrol agent against brown marmorated stink bug; T. basalis (Wollaston), a biocontrol agent introduced against Nezara viridula L. in 1949; and T. oenone Johnson, a native Australasian pentatomid parasitoid. Eight compounds associated with stink bugs elicited antennal responses from all three parasitoids, and we were able to identify seven of these. (E)-2-hexenal, (E)-4-oxo-2-hexenal, (E)-2-octenal and (E)-2-decenal generally elicited stronger responses in the three parasitoids, while n-tridecane, n-dodecane, and (E)-2-decenyl acetate elicited weaker responses. We discuss how and why the results from electrophysiological experiments can be applied to non-target risk assessments within biological control programmes.

Stick insects (Phasmatodea) have many different oviposition strategies, reflecting a range of adaptive behaviours and morphologies to best place and secure eggs in their environments. Oviposition strategies in Aotearoa New Zealand phasmids are not well documented, but the literature so far suggests that they drop individual eggs to the ground from their position in the foliage. Here, we present evidence for an oviposition strategy unique among the Ro stick insects of Aotearoa New Zealand. Individual female Spinotectarchus acornutus were observed inserting their eggs in a range of substrates, in particular the bark of trees and in spaces within the textured surfaces of tree fern trunks. We also highlight how the specific morphology of their eggs may be an adaptation to assist in substrate attachment, while their elongated secondary ovipositor could aid in egg insertion into substrates.

Within-species variation in colour phenotypes is widespread in animals. One mechanism by which such variation can be maintained is plastic background matching, where individuals plastically develop a similar colour to that of their surroundings. A few examples are known from insects that exhibit green-brown colour polyphenisms. But the extent to which plastic colour responses are shaped by other factors, such as genetic variation in plasticity or the interaction of other environmental cues, is poorly understood.Here, we investigate the plasticity of body coloration in the springbok mantis, Miomantis caffra-a species where hatchlings emerge brown in colour and typically change to green but sometimes remain entirely or partly brown through successive moults. We reared 350 mantises from 10 full-sib families on a green or brown background under a high or low temperature and a high or low humidity using a fully factorial, split-brood design, and recorded colour phenotypes (all green, all brown or mixed coloration) after 14 weeks of development.We found very strong evidence of developmental plasticity for background matching: The green background induced a higher incidence of the all-green phenotype, whereas the brown background produced more of the all-brown and mixed phenotypes. The all-green phenotype was also universally more common under higher humidity, and under higher temperature when the background was green. However, not all body parts showed the same level of environmental sensitivity: The steepest reaction norms were observed in the mid-legs and hindlegs, potentially reflecting selection for disruptive coloration of the body outline in browner environments. Using model comparison techniques, we found little evidence of genotype-level variation in colour plasticity-a pattern likely the result of strong viability selection for camouflage.Our study shows how developmental plasticity in coloration can be triggered directly by the colour of the environment and indirectly by climatic cues associated with habitat coloration. We argue that this high level of developmental plasticity has likely evolved due to the diversity of habitats but sedentary lifestyle of this sit-and-wait predator.Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog.image

When resources such as mates or mating sites are limited, selection drives the evolution of complex and frequently violent fighting behaviour. Contest outcome is determined by an individual's resource holding potential (RHP) in comparison to that of their opponent. During contests individuals may assess only their own RHP, or they may mutually assess both their own and their opponent's RHP to determine the effort they allocate to a contest. Male giraffe weevils (Lasiorhynchus barbicornis) bear an elongated rostrum used as a weapon during intense fights over access to females. We used sequential analysis to target the fine-scale structure of contests and phases of contest escalation to determine the assessment strategy used by rival male giraffe weevils in the wild. We found significant non-random temporal structure in behavioural transitions in all transition matrices, and winner and loser transition matrices were significantly different. Contest de-escalation was extremely rare compared to escalation and winners and losers used very different behaviours during contests overall. This study provides support for the sequential assessment model of mutual assessment by male giraffe weevils during competitive interactions. It also demonstrates the utility of sequential analysis in making sense of the often complex interactions occurring in wild insect populations.

As the increasing globalisation of trade generates an escalating spread of arthropod pests, eradication has gained traction as a viable approach to avoiding the growing long-term management costs. The Sterile Insect Technique (SIT) involves releasing sexually sterile insects into the wild population and has been employed for environmentally friendly eradication. Alternatively, classical biological control (CBC) comprises the importation and release of natural enemies. Although generally used for long-term management, evidence suggests a synergistic impact could be exerted on pest populations when combined with SIT, potentially improving eradication outcomes. It is possible that sterile parasitoids, which would not bear the risk of irreversible non-target impacts associated with conventional CBC releases, could be accepted by regulatory agencies as a safe option to be used as a synergistic component of eradication. We investigated the post-irradiation behaviour and fitness of the egg parasitoid Trissolcus basalis to determine whether irradiation-induced sterility may reduce its efficacy. In comparing sterile and non-sterile parasitoids, there were no observable differences in searching behaviour, no significant differences in the number of egg masses found and parasitised, nor longevity. It is possible that sterile parasitoid release could contribute to an eradication programme without detrimental effects.

Due to ongoing climate change and the spread of invasive pests, understanding and predicting climatic suitability for invasive insect species has shown growing demand from government and industry biosecurity managers. The invasive pest Bactericera cockerelli , (Šulc) (Hemiptera: Triozidae), commonly known as tomato potato psyllid (TPP), is native to North America and has recently invaded Australasia. TPP is also the vector of the bacterial plant pathogen Candidatus Liberibacter solanacearum (CLso), which has caused severe economic losses for potato growers worldwide. We used the niche modelling software CLIMEX to predict the potential geographical distribution of TPP in Australasia and worldwide under current and future climatic scenarios. Our model prediction of the current climate conditions closely agrees with all the known distributions of TPP. In its native range (North America), TPP is predicted to expand its current geographical range in semi‐arid, temperate, and continental climates. Within Australia, along with the known occurrence of TPP in Western Australia, potential expansion into South Australia, Victoria, New South Wales and Queensland is predicted. The predicted distribution closely matches all the known records with higher climatic suitability in New Zealand. Globally, the model projected that the pest‐free countries in Europe and East Asia are climatically more suitable for TPP. Predictions under the future climate change scenarios (A1B, CSIRO Mk 3.0 for 2090) showed a significant reduction of the known geographical range of TPP with a possible expansion towards higher latitudes. Areas in North America and Australia are projected to be less climatically suitable for the survival of TPP in future climates. However, our model suggested that Europe and New Zealand will remain unchanged or will become more favourable in the future. These CLIMEX projections for current and future climatic distribution provide valuable information for existing and future biosecurity preparedness and management programmes, which may prove helpful in risk assessments and identifying potential areas that are likely to be susceptible to a TPP invasion.

Intraspecific weapon polymorphisms that arise via conditional thresholds may be affected by juvenile experience such as predator encounters, yet this idea has rarely been tested. The New Zealand harvestman Forsteropsalis pureora has three male morphs: majors (alphas and betas) are large-bodied with large chelicerae used in male-male contests, while minors (gammas) are small-bodied with small chelicerae and scramble to find mates. Individuals use leg autotomy to escape predators and there is no regeneration of the missing leg. Here, we tested whether juvenile experience affects adult morph using leg autotomy scars as a proxy of predator encounters. Juvenile males that lost at least one leg (with either locomotory or sensory function) had a 45 times higher probability of becoming a minor morph at adulthood than intact juvenile males. Leg loss during development may affect foraging, locomotion, and/or physiology, potentially linking a juvenile's predator encounters to their final adult morph and future reproductive tactic.

Noncopulatory cannibalism, which occurs when females attack and consume males instead of mating with them, could persist if it increases female fecundity more than it exacerbates reproductive failure. However, females that are facultatively parthenogenetic may be able to cannibalize indiscriminately since securing a mate is not necessary for reproduction when parthenogenesis is possible. We used an experimental approach to examine the economics of cannibalism with and without mating for female Miomantis caffra, a facultatively parthenogenetic mantis that shows high rates of noncopulatory cannibalism. If noncopulatory cannibalism is maintained by fecundity enhancement, we predicted that eating a male would boost female fitness regardless of mating status. If noncopulatory cannibalism persists by facilitating total mating avoidance, then we predicted that mating would be costly, and females would perform better via parthenogenesis than via sex. Contrary to our predictions, we found that mating once led to dramatically higher fitness than not mating, and cannibalizing a single male provided no overall fitness benefit to either mated or unmated females. Our results suggest that precopulatory cannibalism persists in M. caffra for reasons other than fecundity enhancement or total mating avoidance. (c) 2023 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Background matching is perhaps the most ubiquitous form of defensive camouflage in the animal kingdom, an adaptive strategy that relies on the visual resemblance between a prey organism and its background to promote concealment from predators. The importance of background matching has been acknowledged for over a century, yet despite its renown and apparent pervasiveness, few studies exist that have objectively quantified its occurrence and tested the functional significance of background matching in a specific animal study system. The North Island lichen moth Declana atronivea presents a fascinating system to investigate such anti-predator coloration. This species possesses high contrast black and white forewings that appear to resemble lichen. Here we assessed the contribution of background matching to the antipredator defence of D. atronivea using field predation experiments with realistic models. We found that D. atronivea coloration confers a significant survival advantage against native avian predators when on lichen backgrounds compared to bark backgrounds, with an intermediate level of predation occurring when models were near, but not on lichen. This suggests that D. atronivea wing patterns are an adaptation for background matching. We subsequently used calibrated digital photography, avian vision modelling and image analysis techniques to objectively quantify the degree of background matching exhibited by D. atronivea and assessed the contribution of different visual elements (colour, luminance and pattern) to camouflage in this species. Only the pattern elements of D. atronivea presented a close match to that of the lichen backgrounds, with both chromatic and achromatic cues found to be poor predictors of background matching in this species. This study is one of the first to integrate vision modelling, quantitative image analysis and field predation experiments using realistic models to objectively quantify the level and functional significance of background matching in a real species, and presents an ideal system for further investigating the interrelation between multiple mechanisms of camouflage.

Across the animal kingdom, exaggerated weaponry is frequently used by one sex to contest access for potential mates. Within species, if disproportionate investment in weaponry confers an advantage to larger individuals, this may result in positive static allometry. It is predicted that the same selective pressures may also lead to positive evolutionary allometry, where larger species bear disproportionately large weapons on average, compared with smaller species. Furthermore, in species with stronger sexual selection, the static allometries of those weapons are expected to steepen. All adult males across the New Zealand sheetweb spider genus Cambridgea bear exaggerated chelicerae, which are used to compete for control of females' webs. Here, we characterize the distribution of chelicera lengths within each sex of 12 Cambridgea species to show that chelicerae almost always exhibit positive static allometry in males while female chelicera lengths are consistently isometric. We use comparative phylogenetic methods to demonstrate that the slopes of static allometries steepen in males of larger species but that the ratio of average chelicera length to cephalothorax width is tightly conserved across taxa, leading to an isometric evolutionary allometry. While static allometries indeed steepen in larger species, possibly due to stronger sexual selection, this conservation of relative trait size suggests that chelicera length is subject to other stabilizing selective pressures. Changes to species body plans might be constrained, while still allowing for disproportionate investment in weapon traits in the upper range of intraspecific body sizes.

Retrospective host range testing is essential for understanding the physiological host range of introduced biological control agents (BCAs) and updating forecasts of non-target risks. It is especially important to conduct this work if there was no host range testing prior to release of the agent. Trissolcus basalis Wollaston was released in New Zealand in 1949 against green vegetable bug (Nezara viridula [L.]), but host range testing was never undertaken, and subsequent work in the 1960s was only of a qualitative nature and remains incomplete. The hostparasitoid complex between New Zealand pentatomids, T. basalis, and the native pentatomid parasitoid Trissolcus oenone Dodd, is therefore poorly understood. We conducted no-choice oviposition tests between the two resident Trissolcus species and all available New Zealand pentatomid species to characterise the physiological (=fundamental) host ranges of these parasitoids. We present the results of the first retrospective host-specificity study on T. basalis in New Zealand. Our results show T. basalis attacks and develops in all nine pentatomid taxa we exposed it to (including the endemic alpine species Hypsithocus hudsonae Bergroth), while T. oenone attacks and develops in seven out of eight pentatomid species we tested it against (and its capacity to attack H. hudsonae remains unknown). Parasitism efficiencies for all treatments exceeded 60%, while development times were similar for both parasitoids regardless of host. We discuss the importance of physiological host range testing for understanding potential non-target effects. Trissolcus japonicus Ashmead (Hymenoptera: Scelionidae) was recently approved for release in New Zealand against brown marmorated stink bug Halyomorpha halys Stal (Hemiptera: Pentatomidae), subject to its potential establishment, and we examine our results in the context of potential competition between introduced parasitoids for non-target species.

The coast provides an important habitat for insects throughout the world. Some insect taxa are entirely dependent on this continuous but narrow strip of habitat between the land and sea, despite the challenging environmental conditions. In Aotearoa|New Zealand (hereafter Aotearoa), the coastal environment is extensive and varies enormously. Aotearoa is also home to a diverse and predominantly endemic Diptera fauna of roughly 5500 species, and a small but significant proportion of these are found along the coast. Here we provide the first extensive survey of Aotearoa’s coastal flies, and describe how the diversity, richness, and abundance of specialised wrack-inhabiting communities vary. Overall, we recorded 257 different species collected from 109 sites from around Aotearoa’s three main islands, with highest abundance, species richness and diversity all found at South Island sites. Our surveys are estimated to have captured over 80% of the species occupying the seashore, and 100% of the wrack specialist community, for which we identified a country-wide baseline community. This study has provided new and interesting insights into the distribution and diversity of flies in Aotearoa. It also highlights the importance of carrying out broad community surveys to capture and improve our understanding of our local fauna.