Specialist Insect Research Articles

Detoxification of Plant Aromatic Abietanoids via Cleavage of the Benzene Ring into 11,12-Seco-diterpene Polyenes by a Specialist Insect of Leucosceptrum canum.

Leaves of Leucosceptrum canum harbor abundant toxic aromatic abietanoids, and they are rarely attacked by insect herbivores, except for the larvae of Nacna malachitis. The excrements of the insect that fed on L. canum leaves were investigated, leading to the isolation and identification of two unprecedented 11,12-seco-abietane diterpene polyenes: nacnabietanins A (1) and B (2). This discovery heralds a unique detoxification mechanism of plant aromatic abietanoids by insects through enzymatic cleavage of stable benzene rings into more easily degraded polyenes.

Configuration and Location of Small Urban Gardens Affect Colonization by Monarch Butterflies

Ecological theory predicts that specialist insect herbivores are more likely to locate and colonize host plants growing in relatively sparse or pure stands compared to host plants growing amongst diverse non-host vegetation. We tested the hypothesis that increasing the apparency and accessibility of milkweed (Asclepias spp.) host plants in small polyculture gardens would boost their colonization by the monarch butterfly (Danaus plexippus), an iconic native species of conservation concern. We established replicated gardens containing the identical mix of milkweeds, flowering nectar sources, and non-host ornamental grasses but arranged in three different spatial configurations that were monitored for monarch colonization over two successive growing seasons. Monarch eggs and larvae were 2–3 times more abundant in gardens having milkweeds evenly spaced in a 1-m corridor around the perimeter, surrounding the nectar plants and grasses, than in gardens in which milkweeds were surrounded by or intermixed with the other plants. Predator populations were similar in all garden designs. In a corollary open-field experiment, female monarchs laid significantly more eggs on milkweed plants that were fully accessible than on milkweeds surrounded by non-host grasses of equal height. In addition, we monitored monarch usage of 22 citizen-planted gardens containing milkweed and nectar plants in relation to their botanical composition, layout, and surrounding hardscape. Multivariate analysis explained 71% of the variation, with significantly more eggs and larvae found in gardens having milkweeds spatially isolated as opposed to closely intermixed with non-host plants, and in gardens having 100 m north/south access unimpeded by structures. Numerous programs encourage citizens to establish gardens with milkweed and nectar plants to help offset habitat loss across the monarch's breeding range. Our findings suggest guidelines for garden design that can help make the urban sector's contributions to monarch habitat restoration more rewarding for participants, and of greater potential value to monarch recovery.

Leaf trichomes in Metrosideros polymorpha can contribute to avoiding extra water stress by impeding gall formation.

Plants inhabiting arid environments tend to have leaf trichomes, but their adaptive significance remains unclear. Leaf trichomes are known to play a role in plant defence against herbivores, including gall makers. Because gall formation can increase water loss partly through increased surface area, we tested the novel hypothesis that leaf trichomes could contribute to avoiding extra water stress by impeding gall formation, which would have adaptive advantages in arid environments. We focused on Metrosideros polymorpha, an endemic tree species in the Hawaiian Islands, whose leaves often suffer from galls formed by specialist insects, Hawaiian psyllids (Pariaconus spp.). There is large variation in the amount of leaf trichomes (0-40 % of leaf mass) in M. polymorpha. Three gall types are found on the island of Hawaii: the largest is the 'cone' type, followed by 'flat' and 'pit' types. We conducted laboratory experiments to quantify the extent to which gall formation is associated with leaf water relations. We also conducted a field census of 1779 individuals from 48 populations across the entire range of habitats of M. polymorpha on the island of Hawaii to evaluate associations between gall formation (presence and abundance) and the amount of leaf trichomes. Our laboratory experiment showed that leaf minimum conductance was significantly higher in leaves with a greater number of cone- or flat-type galls but not pit-type galls. Our field census suggested that the amount of trichomes was negatively associated with probabilities of the presence of cone- or flat-type galls but not pit-type galls, irrespective of environmental factors. Our results suggest that leaf trichomes in M. polymorpha can contribute to the avoidance of extra water stress through interactions with some gall-making species, and potentially increase the fitness of plants under arid conditions.

The entomofauna on Eucalyptus in Israel: A review

The first successful Eucalyptus stands were planted in Israel in 1884. This tree genus, particularly E. camaldulensis, now covers approximately 11,000 ha and constitutes nearly 4% of all planted ornamental trees. Here we review and discuss the information available about indigenous and invasive species of insects that develop on Eucalyptus trees in Israel and the natural enemies of specific exotic insects of this tree. Sixty-two phytophagous species are recorded on this tree of which approximately 60% are indigenous. The largest group are the sap feeders, including both indigenous and invasive species, which are mostly found on irrigated trees, or in wetlands. The second largest group are wood feeders, polyphagous Coleoptera that form the dominant native group, developing in dying or dead wood. Most of the seventeen parasitoids associated with the ten invasive Eucalyptus-specific species were introduced as biocontrol agents in classical biological control projects. None of the polyphagous species recorded on Eucalyptus pose any threat to this tree. The most noxious invasive specific pests, the gall wasps (Eulophidae) and bronze bug (Thaumastocoris peregrinus), are well controlled by introduced parasitoids. Potential entomological hazards of Eucalyptus in Israel are most likely to originate from the Australian insect fauna.

Spatial and temporal patterns of a pulsed resource dynamically drive the distribution of specialist herbivores

Patterns and drivers of the spatio-temporal distribution of herbivores are key elements of their ecological and evolutionary impacts on plant populations. Herbivore spatial distributions may be influenced by increased (RCH: resource concentration hypothesis) or decreased (RDH: resource dilution hypothesis) resource densities, but the effect of temporal variations in resource densities on such distributions remains poorly documented. We used a survey of a masting tree species and its seed predators in Southeastern France to address the effect of a host’s pulsed resource on the spatio-temporal distributions of highly specialized insect herbivores feeding on seeds. Variations in both resource and seed predator densities were assessed by estimating seed production and seed infestation rates in focus trees during 10 consecutive years. We found increasing seed infestation rates with decreasing host tree densities in years of low seed production, indicating a RDH pattern of seed predators. However, such pattern was not persistent in years of high seed production during which seed infestation rates did not depend on host tree densities. We showed that temporal variations in resource density can lead to transience of seed predator spatial distribution. This study highlights how predictions of plant-herbivore interactions in natural ecosystems may rely on temporal components underlying RCH and RDH hypotheses.

How do herbivorous insects respond to drought stress in trees?

Increased frequency and severity of drought, as a result of climate change, is expected to drive critical changes in plant-insect interactions that may elevate rates of tree mortality. The mechanisms that link water stress in plants to insect performance are not well understood. Here, we build on previous reviews and develop a framework that incorporates the severity and longevity of drought and captures the plant physiological adjustments that follow moderate and severe drought. Using this framework, we investigate in greater depth how insect performance responds to increasing drought severity for: (i) different feeding guilds; (ii) flush feeders and senescence feeders; (iii) specialist and generalist insect herbivores; and (iv) temperate versus tropical forest communities. We outline how intermittent and moderate drought can result in increases of carbon-based and nitrogen-based chemical defences, whereas long and severe drought events can result in decreases in plant secondary defence compounds. We predict that different herbivore feeding guilds will show different but predictable responses to drought events, with most feeding guilds being negatively affected by water stress, with the exception of wood borers and bark beetles during severe drought and sap-sucking insects and leaf miners during moderate and intermittent drought. Time of feeding and host specificity are important considerations. Some insects, regardless of feeding guild, prefer to feed on younger tissues from leaf flush, whereas others are adapted to feed on senescing tissues of severely stressed trees. We argue that moderate water stress could benefit specialist insect herbivores, while generalists might prefer severe drought conditions. Current evidence suggests that insect outbreaks are shorter and more spatially restricted in tropical than in temperate forests. We suggest that future research on the impact of drought on insect communities should include (i) assessing how drought-induced changes in various plant traits, such as secondary compound concentrations and leaf water potential, affect herbivores; (ii) food web implications for other insects and those that feed on them; and (iii) interactions between the effects on insects of increasing drought and other forms of environmental change including rising temperatures and CO2 levels. There is a need for larger, temperate and tropical forest-scale drought experiments to look at herbivorous insect responses and their role in tree death.

Transcriptome responses to different herbivores reveal differences in defense strategies between populations of Eruca sativa

BackgroundIntraspecific variations among induced responses might lead to understanding of adaptive variations in defense strategies against insects. We employed RNA-Seq transcriptome screening to elucidate the molecular basis for phenotypic differences between two populations of Eruca sativa (Brassicaceae), in defense against larvae of the generalist and specialist insects, Spodoptera littoralis and Pieris brassicae, respectively. The E. sativa populations originated from desert and Mediterranean sites, where the plants grow in distinct habitats.ResultsResponses to elicitation of the plants’ defenses against wounding and insect herbivory resulted in more upregulated transcripts in plants of the Mediterranean population than in those of the desert. PCA analysis differentiated between the two populations and between the elicitation treatments. Comprehensive analysis indicated that defense responses involved induction of the salicylic acid and jasmonic acid pathways in plants of the desert and Mediterranean populations, respectively. In general, the defense response involved upregulation of the aliphatic glucosinolates pathway in plants of the Mediterranean population, whereas herbivory caused downregulation of this pathway in desert plants. Further quantitative RT-PCR analysis indicated that defense response in the desert plants involved higher expression of nitrile-specifier protein (NSP) than in the Mediterranean plants, suggesting that in the desert plants glucosinolates breakdown products are directed to simple-nitriles rather than to the more toxic isothiocyanates. In addition, the defense response in plants of the desert population involved upregulation of flavonoid synthesis and sclerophylly.ConclusionsThe results indicated that differing defense responses in plants of the two populations are governed by different signaling cascades. We suggest that adaptive ecotypic differentiation in defense strategies could result from generalist and specialist herbivore pressures in the Mediterranean and desert populations, respectively. Moreover, the defense responses in plants of the desert habitat, which include upregulation of mechanical defenses, also could be associated with their dual role in defense against both biotic and abiotic stresses.

The nutritional landscape of host plants for a specialist insect herbivore.

Nutrition has far‐reaching effects on both the ecology and evolution of species. A substantial body of work has examined the role of host plant quality on insect herbivores, with a particular focus on specialist–generalist dynamics, the interaction of growth and other physiological attributes on fitness and tritrophic effects. Measures of plant quality usually involve one or two axes of nutritional space: typically secondary metabolites or elemental proxies (N and C) of protein and carbohydrates, respectively.Here, we describe the nutrient space of seven host plants of the specialist insect herbivore, Manduca sexta, using an approach that measures physiologically relevant sources of nutrition, soluble protein and digestible carbohydrates. We show that plant species differ markedly in their nutrient content, offering developing insect herbivores a range of available nutrient spaces that also depend on the age of the leaves being consumed.The majority of host‐plant species produce diets that are suboptimal to the herbivore, likely resulting in varying levels of compensatory feeding for M. sexta to reach target levels of protein to ensure successful growth and development. Low‐quality diets can also impact immune function leading to complex patterns of optimization of plant resources that maximizes both growth and the ability to defend from parasitoids and pathogens. This study is the first to quantify the nutrient space of a suite of host plants used by an insect herbivore using physiologically relevant measures of nutrition.

Plant defense resistance in natural enemies of a specialist insect herbivore

Plants defend themselves against herbivores through the production of toxic and deterrent metabolites. Adapted herbivores can tolerate and sometimes sequester these metabolites, allowing them to feed on defended plants and become toxic to their own enemies. Can herbivore natural enemies overcome sequestered plant defense metabolites to prey on adapted herbivores? To address this question, we studied how entomopathogenic nematodes cope with benzoxazinoid defense metabolites that are produced by grasses and sequestered by a specialist maize herbivore, the western corn rootworm. We find that nematodes from US maize fields in regions in which the western corn rootworm was present over the last 50 y are behaviorally and metabolically resistant to sequestered benzoxazinoids and more infective toward the western corn rootworm than nematodes from other parts of the world. Exposure of a benzoxazinoid-susceptible nematode strain to the western corn rootworm for 5 generations results in higher behavioral and metabolic resistance and benzoxazinoid-dependent infectivity toward the western corn rootworm. Thus, herbivores that are exposed to a plant defense sequestering herbivore can evolve both behavioral and metabolic resistance to plant defense metabolites, and these traits are associated with higher infectivity toward a defense sequestering herbivore. We conclude that plant defense metabolites that are transferred through adapted herbivores may result in the evolution of resistance in herbivore natural enemies. Our study also identifies plant defense resistance as a potential target for the improvement of biological control agents.

Host-Plant Specific Feeding Relationships and Insect Developmental Stage Modulate the Impact of Rainfall on Diamondback Moth Larvae.

The impact of simulated rainfall on diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), larvae depends on their stage-specific feeding behavior, physical characteristics, and host plants. Neonates released at typical oviposition sites on Chinese cabbage (Brassica rapa var. pekinensis L. [Brassicales: Brassicaceae]) plants moved less (3-72 cm) and spend shorter periods (>1 h) than it has been previously reported for common cabbage (Brassica oleracea var. capitata L. [Brassicales: Brassicaceae]) (>80 cm and >3 h, respectively) before establishing feeding sites. On both host plants, larvae spent longer on the abaxial surfaces of leaves and were more likely to establish mines there than on the adaxial surfaces. On Chinese cabbage plants, ≈40% of neonates were removed when exposed to rainfall (5.6 cm/h for 3 min) within 5 min of release. Larval losses decreased rapidly as the interval between release and rainfall exposure increased and exposure to rainfall 2 h after release did not affect survival. On common cabbage plants, ≈65% of neonates were removed when exposed to rainfall within 30 min of release, losses decreased as the interval between release and rainfall exposure increased, but they decreased more slowly than on Chinese cabbage, and rainfall caused significant larval mortality up to 4 h after release. Rainfall also affected later instar larvae (susceptibility: 2nd> 3rd = 4th) but neither the susceptibility of these larvae nor that of pupae was affected by the host plant. Wet leaf surfaces disrupted movement and feeding site establishment by neonates. When dislodged from plants on to the surface of wet soil, most later stage larvae could relocate host plants, but most neonates could not.

Phytochemical defences and performance of specialist and generalist herbivores: a meta‐analysis

1. Phytochemical coevolution theory, a long‐standing paradigm in plant–insect interactions, predicts that specialist herbivores are less negatively affected by the allelochemicals of their host plants than are generalist herbivores. Although this theory is prevalent in plant–insect science, it is not always supported by empirical studies measuring the performance of specialist and generalist insects in response to allelochemicals.2. The present study aimed to investigate: (i) whether there a difference between specialist and generalist performance in response to allelochemicals and (ii) whether the effect of allelochemicals on specialists and generalists depend upon allelochemical class or insect order.3. A meta‐analysis was conducted incorporating 76 effect sizes drawn from studies that directly compared the performance of specialist and generalist insects in response to treatment and control diets. Most of the effect sizes were related to the performance metric growth, the insect order Lepidoptera, and the allelochemical class nitrogen‐containing compounds.4. As predicted by phytochemical coevolution theory, specialist insects responded less negatively to allelochemicals of their hosts than generalist insects in terms of growth. There were no significant differences in terms of fecundity or survival, or among allelochemical classes or insect orders.5. These results support the prediction of phytochemical coevolution theory that specialist insects respond less negatively to allelochemicals of their hosts than generalists, although only in terms of growth.

Host plant associations and geography interact to shape diversification in a specialist insect herbivore.

Disentangling the processes underlying geographic and environmental patterns of biodiversity challenges biologists as such patterns emerge from eco-evolutionary processes confounded by spatial autocorrelation among sample units. The herbivorous insect, Belonocnema treatae (Hymenoptera: Cynipidae), exhibits regional specialization on three plant species whose geographic distributions range from sympatry through allopatry across the southern United States. Using range-wide sampling spanning the geographic ranges of the three host plants and genotyping-by-sequencing of 1,217 individuals, we tested whether this insect herbivore exhibited host plant-associated genomic differentiation while controlling for spatial autocorrelation among the 58 sample sites. Population genomic structure based on 40,699 SNPs was evaluated using the hierarchical Bayesian model entropy to assign individuals to genetic clusters and estimate admixture proportions. To control for spatial autocorrelation, distance-based Moran's eigenvector mapping was used to construct regression variables summarizing spatial structure inherent among sample sites. Distance-based redundancy analysis (dbRDA) incorporating the spatial variables was then applied to partition host plant-associated differentiation (HAD) from spatial autocorrelation. By combining entropy and dbRDA to analyse SNP data, we unveiled a complex mosaic of highly structured differentiation within and among gall-former populations finding evidence that geography, HAD and spatial autocorrelation all play significant roles in explaining patterns of genomic differentiation in B.treatae. While dbRDA confirmed host association as a significant predictor of patterns of genomic variation, spatial autocorrelation among sites explained the largest proportion of variation. Our results demonstrate the value of combining dbRDA with hierarchical structural analyses to partition spatial/environmental patterns of genomic variation.

Geography is more important than host plant use for the population genetic structure of a generalist insect herbivore.

Population divergence can occur due to mechanisms associated with geographic isolation and/or due to selection associated with different ecological niches. Much of the evidence for selection-driven speciation has come from studies of specialist insect herbivores that use different host plant species; however, the influence of host plant use on population divergence of generalist herbivores remains poorly understood. We tested how diet breadth, host plant species and geographic distance influence population divergence of the fall webworm (Hyphantria cunea; FW). FW is a broadly distributed, extreme generalist herbivore consisting of two morphotypes that have been argued to represent two different species: black-headed and red-headed. We characterized the differentiation of FW populations at two geographic scales. We first analysed the influence of host plant and geographic distance on genetic divergence across a broad continental scale for both colour types. We further analysed the influence of host plant, diet breadth and geographic distance on divergence at a finer geographic scale focusing on red-headed FW in Colorado. We found clear genetic and morphological distinction between red- and black-headed FW, and Colorado FW formed a genetic cluster distinct from other locations. Although both geographic distance and host plant use were correlated with genetic distance, geographic distance accounted for up to 3× more variation in genetic distance than did host plant use. As a rare study investigating the genetic structure of a widespread generalist herbivore over a broad geographic range (up to 3,000km), our study supports a strong role for geographic isolation in divergence in this system.

곤충 식품의 섭취 의향에 관한 연구 : 곤충 식품 경험자와 비경험자의 비교를 중심으로

The purpose of this study is to identify the factors that affect consumers’ willingness to eat insects, and also to determine if the factors that affect their willingness to eat insects are dependent on whether or not they are experienced with eating insects. The survey polled 330 nationwide consumers who were in their 20s and 40s. The study found that the consumers who had experience eating insects were more willing to eat them again. For the experienced people, insects as a nutritional food, uncomfortable feeling and age variables affected their intake intention. For non-experienced people, the effects of uncomfortable feeling, nutritional food as a specific target, the advantages of insect food, indifference, and an emphasis on the appearance of insect food were found to affect consumption of insects. Insect food experience has been shown to affect consumers’ willingness to eat insect food. Consumers’ innovation has been shown to have something to do with their experience with insect food, but this does not have a direct impact on their willingness to eat insect food. The variable that have the greatest impact on the desire for consuming insect food is nutritional foods development for specific targeting. This means that consumers should be aware of the specific nutritional efficacy of insect food and recognize it as a beneficial product. Therefore, consumer education will be needed to emphasize the benefits of specific insect food in the future.

Growth performance and nutritional profile of mealworms reared on corn stover, soybean meal, and distillers’ grains

Mealworms are commercially reared on diets comprising of mixed grains. Substituting grains with agro-food industry by-products creates opportunities to valorize by-products and lowers the cost of insect rearing practices. In this study, three by-products (mushroom spent corn stover, highly denatured soybean meal, and spirit distillers’ grains) as treatments and wheat bran as control were used to rear mealworms. For growth performance, mealworms dry weights reared on three by-products were 53–67% of control. Feed conversion and utilization ratios ranged from 36 to 45% and 50 to 57% of control, respectively. For nutritional profile, protein and fat fractions ranged from 70 to 76% and 6 to 12% of mealworm dry weight, respectively. Leucine, lysine, methionine + cysteine, threonine, and valine were the limiting amino acids comparing with FAO/WHO requirements. The major fatty acids were linoleic acid (C18:2, 30–38%), oleic acid (C18:1, 24–34%), and palmitic acid (C16:0, 14–17%). The comparable nutritional profile demonstrated the potential to rear mealworms using these three cheap by-products. The results provide a reference for insect farmers to formulate the diets for obtaining specific insect products with desired nutrient composition.

Impact of necrophagous insects on the emission of volatile organic compounds released during the decaying process

After death, corpses undergo a complex decomposition process, during which volatile organic compounds (VOCs) are released. Several groups of organisms, including insects, use these VOCs to select their mating and feeding sites. While the presence of insects on a corpse influences the decaying process, we do not know whether insects impact on the VOC profile released by the cadaver. Using decomposing rats exposed to dipterans ( Lucilia sericata ) and/or coleopterans ( Dermestes frischii ), we assessed how the presence of insects impacted the cadaver volatilome by using dynamic sampling. As expected, the decomposition of rats in presence of insects was faster than in absence of insects. All rats went through the five decomposition stages with the exception of rats decomposing without insects. The composition of their volatile profiles differed among decomposition stages. We also found that insects do not affect the volatilome of decomposing rats, and no indicator compound could be associated to the presence of specific insect groups.

Generalist and specialist Metarhizium insect pathogens retain ancestral ability to colonize plant roots

Abstract Metarhizium is widely recognized as an insect pathogenic fungus but it can also form symbiotic associations with plant roots. Here we assessed root rhizoplane, as well as endophytic colonization in monocots and dicots by ten Metarhizium strains representing species with either narrow or broad insect host ranges, as well as a related endophytic and nematophagous fungus, Pochonia chlamydosporia. In addition, insect pathogenicity of these strains was evaluated against mealworm (Tenebrio molitor), wax moth (Galleria mellonella) larvae and grasshoppers (Melanoplus sanguinipes). We found that all Metarhizium strains and Pochonia colonized the rhizoplane and rhizosphere of roots with varying degrees on all plants assessed. All Metarhizium strains tested showed a preference for endophytic colonization of monocot plants (within 20 d) when compared to dicots. While generalists showed pathogenicity towards all tested insect hosts, the specialists showed pathogenicity only towards grasshoppers, whereas Pochonia was avirulent towards insects. We observed variation in ability to colonize the rhizosphere amongst Metarhizium species. However, regardless of whether the Metarhizium species was a generalist or specialist insect pathogen, all strains tested retain ancestral ability to associate with plant roots.

Odors from phylogenetically-distant plants to Brassicaceae repel an herbivorous Brassica specialist

Specialist insect herbivores are constrained by highly specific odor recognition systems to accept suitable host plants. Given that odor recognition leads specialist insects to accept a limited range of plants, we hypothesized that phylogenetically distant plants produce odors that are physicochemically different from host odors and would be less attractive or even repellent to a specialist herbivore. We tested this hypothesis by examining behavioral and ovipositional responses of swede midge (Contarinia nasturtii, Diptera: Cecidomyiidae), a specialist of brassicas, to broccoli sprayed with non-host essential oils. Specifically, we asked: (1) How do essential oils from different plant species influence host-seeking and oviposition behaviors of swede midge? (2) Do odors from non-host plants that are not phylogenetically related or physicochemically similar to host plants affect host-seeking or ovipositional behavior of swede midge? In oviposition assays, we found that non-host odors varied in their ability to modify female midge behavior and that phylogenetic relatedness was negatively correlated with larval density. In y-tube assays, we found that female midges most frequently avoided non-host odors that were more similar to brassica odors. Females were less likely to oviposit on or choose any treated host plants, but particularly avoided garlic, spearmint, thyme, eucalyptus lemon, and cinnamon bark treatments. Overall, we found that plant phylogenetic relatedness and odor similarity are related to repellency. Therefore, altering the diversity of plant odors by explicitly accounting for plant phylogenetic distance and odor similarity, relative to host plants, may be an important, underexploited tactic for sustainably managing challenging pests.

Macrophytes promote aquatic insect conservation in artificial ponds

Abstract Farmland ponds promote regional aquatic biodiversity; however, optimally managing these ponds requires knowledge on how the biodiversity differs between ponds across catchments with different land uses. This study investigated the response of macrophytes, both those in the pond and on the bank, as well as dragonfly and water beetle species richness, diversity and composition in artificial ponds, to numerous environmental variables in catchments dominated by three land uses: protected areas (as reference sites), sugarcane‐dominated and forestry‐dominated landscapes, across two seasons. There was a strong association between insect species richness and vegetation cover, particularly sedges (Cyperus spp.) in spring and bulrushes (Typha capensis) in summer. There was also a positive response between insect species richness and sedges up to 70% cover, and bulrushes up to 40% cover, after which there was a decrease. Furthermore, the protected area ponds contained more rare and specialist insect species. Pond size was not a major variable for biodiversity overall. Although there was generally little congruence in composition among the three taxa, dragonflies were a good surrogate for water beetles and floating macrophytes. Well‐vegetated ponds, both in the water and along the margin, are the most suited to promoting biodiversity, as long as the vegetation is not too dense, and not dominated by one plant species. Artificial ponds in production landscapes have great potential for conserving aquatic species, irrespective of land use, as long as there is management for macrophyte density and heterogeneity.

Unveiling the nonlinear optical response of Trictenotoma childreni longhorn beetle.

The wings of some insect species are known to fluoresce under illumination by ultraviolet light. Their fluorescence properties are however, not comprehensively documented. In this article, the optical properties of one specific insect, the Trictenotoma childreni yellow longhorn beetle, were investigated using both linear and nonlinear optical (NLO) methods, including one- and two-photon fluorescence and second harmonic generation (SHG). These three distinct optical signals discovered in this beetle are attributed to the presence of fluorophores embedded within the scales covering their elytra. Experimental evidence collected in this study indicates that the fluorophores are non-centrosymmetric, a fundamental requirement for SHG. This study is the first reported optical behavior of this type in insects. We described how NLO techniques can complement other more convenient approaches to achieve a more comprehensive understanding of insect scales and integument properties.