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•We exposed virgin L. botrana males with females’ pheromones/cuticular compounds.•Virgin males, exposed or not, were presented to females to test mating preference.•Females select ...mates based on chemical cues to enhance reproductive success.•Females avoided mating with exposed males.•Different cues seems to be used according to the timing.
During reproduction, females may boost their fitness by being selective based on direct material benefits provided by the males, such as nuptial gifts. In Lepidoptera, male provides a spermatophore containing nutrients. However, virgin males produce a bigger spermatophore, containing spermatozoa and nutrients, allowing higher female fertility. Lepidoptera females that could detect the sexual status of males may thus prefer a male without previous mating experience (i.e. a virgin male). This mate selection could be achieved by the use of chemical indices, such as sexual pheromones and cuticular compounds, known to be possibly exchanged during reproduction, and which can be indicators of a previous mating experience and known to be possibly sources of information exchanged. In this study, we experimentally presented Lobesia botrana virgin males with females in order for them to be exposed to females’ natural sexual pheromones or cuticular compounds. 12 or 48 h after the exposure of males to either females’ sexual pheromones or cuticular compounds, these males were confronted to naïve females, which have a choice between them or a virgin non-exposed males. We highlighted that, despite producing a spermatophore of similar volume, all exposed virgin males were less likely to mate with females 12 h after exposure, while after 48 h of exposure this is only the case for virgin males exposed to sexual pheromones. L. botrana females may thus discriminate male sexual experience based on chemical cues (either from cues transferred directly from females to males, or from changes in the cuticular or pheromone males’ profile) indicating past mating experiences. Mating duration was longer for males exposed to sexual pheromones after 12 h only, and for males exposed to cuticular compounds after 48 h only. Pheromones signal might be more persistent over time and seems to more easily gather information for males. The physiological reasoning behind this result still needs to be investigated.
Habitat selection is a critical process that shapes the spatial distribution of species at local and regional scales. The mechanisms underlying habitat preference rely on environmental factors, ...species traits, and ecological interactions with other species. Here, we examined spatial segregation between two co-occurring aphid species (
and
) on wheat plants. We hypothesized that spatial segregation between these aphid species was mediated by aphid cuticular compounds left as chemical "footprints" on plant surfaces. Combining field and laboratory experiments, we first examined how plant microsites alter fitness by measuring the fecundity of each species. Next, we tested whether intra- and interspecific pre-inhabitation modified habitat selection in both aphid species. Both aphid species preferred and exhibited higher fecundity on wheat stems versus leaves. Laboratory trials showed that
pre-inhabitation altered
spatial preference. By gas chromatography-mass spectrometry analysis and bioassays testing the effects of aphid density and footprint extracts, we found a density-dependent response, with
avoiding locations previously inhabited by
. The chemical analysis of footprint crude extracts revealed a highly abundant compound, 1-hexacosanol, and when presented in the synthetic form, also elicited
displacement. Altogether, it indicated that
footprints altered
habitat selection with cuticular compounds playing a relevant role in the habitat selection process in co-occurring aphid species.
The human head lice Pediculus humanus capitis (De Geer) (Phthiraptera: Pediculidae) are strict, obligate human ectoparasites that spends their entire life cycle in the host and cause skin irritation ...and derived infections. Despite the health-related importance, few studies have evaluated the chemical communication among these insects. Here, we evaluate the response of lice of both sexes to cuticular extracts using two solvents of different polarity (hexane and methanol). Cuticular extracts that elicited an attraction response towards head lice were analysed by gas chromatography-mass spectrometry (GC-MS) to determine the cuticular lipid profile. Both lice sexes were attracted to the hexane extracts but not the methanol extracts, suggesting the non-polarity of the compounds present in the cuticle. Chemical analyses of hexane extracts from males and females showed high similarity in major compounds. This study provides the first evidence that lice respond to cuticle extracts, which may be important to understand aggregation behaviour.
A lagarta-parda do eucalipto, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae), vem sendo relatada de forma significativa em povoamentos florestais. A importância econômica de Thyrinteina ...arnobia para o setor florestal na atualidade evidencia a necessidade da consolidação do Manejo Integrado de Pragas Florestais (MIP Floresta), incluindo métodos de monitoramento e controle através de semioquímicos, como o emprego de feromônios. Os compostos químicos voláteis (COVs) em substâncias cuticulares de insetos podem contribuir na regulação da interação entre os indivíduos, sendo objeto de estudo da ecologia química. Dessa forma, objetivou-se realizar uma prospecção dos compostos orgânicos voláteis (COVs) cuticulares em Thyrinteina arnobia e avaliar o papel desses compostos como possíveis feromônios de curta distância. Para o estudo químico de substâncias feromonais, foi realizada a extração de compostos cuticulares (asas e pernas) em Thyrinteina arnobia de machos e fêmeas. Os extratos obtidos foram analisados por cromatografia gasosa com detector de ionização de chamas (GC-FID). Foi realizado um espectro de ação por meio da eletroantenografia acoplada à cromatografia gasosa (CG-EAG) dos extratos de asas e pernas de fêmeas virgens sobre a antena de machos de Thyrinteina arnobia. Contudo, não foi possível observar diferença significativa nas respostas das antenas de machos a nenhum dos estímulos oferecidos. Assim, é possível inferir que Thyrinteina arnobia não faz uso de compostos cuticulares para reconhecimento a curta distância, sendo necessários estudos complementares de comportamento sexual, incluindo observação de corte e cópula.
The coleopteran insects of the Bruchidae family are one of the major pests of stored products like beans and leguminous seeds in general. Bruchids have co-evolved with the seeds of leguminous plants ...dealing with the toxic compounds from the seeds. These insects eat a considerable part of the stored product and also contaminate the grains with their dead bodies, wings, and excreta. Among all the pests, insect damage in stored grains alone could escalate to cause up to 100% loss.
An alternative to managing this pest insect is the use of pheromones. Sex pheromones provide important signals in sexual communication. Generally, volatile sex pheromones are released to attract the opposite sex from a distance, and contact sex pheromones help in partner discrimination and can elicit courtship.
The main focus of this article is to review the results on the chemical identification of pheromones of insect pests of the family Bruchidae in stored products.
•The results on the chemical identification of pheromones of the family Bruchidae were reviewed.•Biological activities of compounds were discussed.•An Integrated Pest Management point of view is given.
The dominance hierarchy in primitively eusocial insect societies has been shown to be mainly regulated through aggressive interactions. Females that are generally more dominant stand out and occupy ...the queen position, meaning that they monopolize reproduction while others perform other tasks. Chemical communication is important for maintaining social cohesion. Cuticular hydrocarbons are recognized as the main molecules responsible for mediating social interactions, especially nestmate recognition and queen signalling. Many highly eusocial groups have been studied in recent years, but primitively eusocial groups, which are key to understanding the evolution of social behavior, remain unexplored. In this study, we investigated the connection between cuticular hydrocarbons in females expressed in different social contexts in the primitively eusocial wasp
Mischocyttarus cerberus
. Colonies in two different ontogenetic phases, pre- and post-worker emergence, were used. We observed and categorized behavioral interactions between individual females and collected all individuals in a nest to obtain information on size, ovary activation and chemical composition. Furthermore, we conducted experiments in which the alpha (dominant) females were removed from nests to produce a new dominance hierarchy. We found that females in different hierarchical positions had small chemical difference corresponding with ovary activity. Our results support the hypothesis that cuticular hydrocarbons are associated with social context in this primitively eusocial species, with some compounds being associated with hierarchical position and ovarian activity.
Vespa velutina
and
V. crabro
are eusocial insects in which chemical communication is decisive for social interactions.
V. velutina
was accidentally introduced in 2004 in France and subsequently in ...northern Spain in 2010. It is an invasive species that severely affects the beekeeping sector. The hornet autochthonous
V. crabro
with a similar ecological niche is captured in bait traps used to control
V. velutina
populations. Insect cuticle and head structures had an important role in chemical communication so that this research approaches for the first time chemical compounds extracted from the heads of
V. velutina
and
V. crabro
. Chemical compounds were profiled using GC/MS. The main compounds identified were carbohydrates, fatty acids, and hydrocarbons. The chemical profile of both species was compared and also an intrinsic differentiation was made between queens and workers in
V. velutina
. Chemometric techniques (PCA and LSD) were used to achieve this goal.
In Portugal, dozens of bark and wood‐boring beetle species have been recorded colonizing Pinus pinaster Aiton (Pinaceae), the main conifer species affected by pine wilt disease (PWD). However, its ...causal agent, the pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle (Parasitaphelenchidae), has been recovered only from the black pine sawyer, Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae). To understand the mechanisms underlying this specific relationship, our goal was to characterize the cuticular compounds (CCs) of three of the most abundant wood‐boring cerambycids, M. galloprovincialis, Arhopalus syriacus (Reiter), and Pogonocherus perroudi (Mulsant) Villiers, colonizing infested P. pinaster. Three methods of extracting CCs were assessed: (1) headspace solid phase microextraction (SPME), (2) extraction with organic solvent (pentane or ethanol), and (3) hydrodistillation. Pentane extraction was most effective, using pooled samples of each of the insects’ developmental stages. Extracts were analysed by gas chromatography‐mass spectrometry (GC‐MS) to identify compounds, and by GC for quantification. The pentane extracts contained predominantly straight‐chain (n‐C) and methyl‐branched hydrocarbons (meC). Cluster analysis defined two main clusters, with cluster A comprising A. syriacus samples dominated by n‐C23 (7‐39%), n‐C25 (9‐31%), and n‐C27 (5‐11%). Pogonocherus perroudi and the larvae from M. galloprovincialis grouped in sub‐cluster B1, characterized by high proportions of n‐C27 (20‐52%), n‐C29 (4‐18%), and 3‐meC27 (8‐18%). Sub‐cluster B2 included the remaining M. galloprovincialis samples, dominated by n‐C27 (10‐14%), n‐C25 (8‐10%), 5‐meC25 (9‐16%), 2‐meC26 (6‐12%), and 3‐meC27 (6‐10%). The CC profiles of the various species may play a key role in triggering the movement of PWN from the tree to callow adults of the specific insect vector, among all insects colonizing infested host trees. Identification of key components would potentially allow the development of valuable tools to manage PWD, for example, in a lure to quickly detect PWN in a tree, or conversely, by treatment of felled wood with PWN repellents to disrupt PWN transfer to its insect vector, breaking the transmission cycle.
To understand the mechanisms underlying the specific relationship between the pinewood nematode (PWN), Bursaphelenchus xylophilus (Parasitaphelenchidae), and its host, the black pine sawyer, Monochamus galloprovincialis (Coleoptera: Cerambycidae), our goal was to characterize the cuticular compounds (CCs) of the three most abundant wood‐boring cerambycids that colonize Pinus pinaster (Pinaceae), the main conifer species affected by pine wilt disease in Portugal. The CC profiles may play a key role in triggering the movement of PWN from the tree to specific insect vectors.
Polyrhachis lamellidens is a temporary social parasitic species. When a newly mated queen encounters a host worker, it opens its jaws and then mounts and rubs the body of the host worker, called ...rubbing behaviour. This behaviour is different from aggressive behaviour and is considered to be a preparatory action before invasion of the host colony. However, it is unclear what cues trigger rubbing behaviour. Therefore, in this study, we used glass beads that imitated the insect body surfaces and searched for triggers. Although P. lamellidens did not respond to the cuticular compounds only, cuticular compounds and chitin coatings on glass beads elicited responses that were similar to those towards live samples. The rubbing behaviour of P. lamellidens was elicited in response to a cuticle-like surface that mimicked a procuticle by combining the compounds with chitin. These results suggest that host recognition and nest-mate recognition are supported by different mechanisms. This article has an associated First Person interview with the first author of the paper.
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