Social insects rely on multimodal communication systems to coordinate both individual and colony-level responses, yet the sensory foundations underlying the perception of combined signal components remain poorly understood. In ants, alarm communication often integrates chemical and vibroacoustic cues, but how these modalities are detected and processed by individual workers is still largely unexplored. In this study, we investigated the peripheral detection of multimodal alarm signals in Myrmica scabrinodis, examining how workers detect concurrent alarm pheromones and stridulations. Our electrophysiological recordings revealed that chemical cues are primarily detected through the antennae, which showed robust responses to pheromones but no detectable sensitivity to vibroacoustic stimuli. Leg recordings provided no conclusive evidence of chemical or vibroacoustic detection, although inconsistent responses to vibroacoustic stimuli in the left hindlegs suggest a potential mechanosensory role that requires further investigation. Chemical and vibroacoustic stimuli are probably detected independently at the peripheral level, likely converging only within central processing pathways in the brain. Moreover, we found evidence of lateralization in sensory detection: the right antenna exhibited greater sensitivity to alarm pheromones than the left, suggesting a left-right bias associated with population-level lateralization previously described in other social insects. Such asymmetries may contribute to enhanced group coordination by imposing consistent physiological biases on signal detection. Taken together, our results provide new insights into the specialization and lateralization of sensory structures involved in ant alarm communication, offering a foundation for further investigation into the neural mechanisms underlying multimodal signal integration in social insects.

The fall armyworm, Spodoptera frugiperda, is a long-distance migratory pest, which invaded the African continent in 2016, causing enormous losses to agricultural crops, especially maize. Synthetic insecticides are primarily used for managing S. frugiperda, but they leave residues on human food and animal feed and also cause environmental hazards. We evaluated the crude ethanolic extract of Piper guineense fruits for contact toxicity on S. frugiperda larvae and determined the lethal concentration (LC50) of the extract. Additionally, we conducted an electrophysiological (EAG) experiment to determine the responses of adult S. frugiperda males and females to P. guineense and determined whether the extract influenced mating, oviposition, and repellence to the adult female. We found that P. guineense extract caused significantly higher mortality to S. frugiperda larvae than an ethanol control. Electrophysiologically, we observed significantly higher responses to the extract than the control, with some variations in response between the sexes. A wind tunnel experiment revealed that females moved more towards the control than towards the extract. Taken together, our results confirm that P. guineense extract is effective against S. frugiperda larvae and adults. Future research should explore the responses of S. frugiperda to P. guineense extract on a field scale.

Phytophagous insects likely select suitable host plants for oviposition based on olfactory and tactile cues. However, details of how insects differentiate among different plant varieties are often unclear. The fall armyworm (Spodoptera frugiperda J. E. Smith) is a highly destructive pest on maize, but little is known about the attraction and oviposition preference of S. frugiperda to different maize varieties, particularly in the context of sub-Saharan Africa, where the insect is a major threat to maize production. We determined the oviposition preference of S. frugiperda females on six different maize plant varieties three of which were hybrid varieties and three were open pollinated varieties, in multiple-choice and no-choice assays. We also evaluated the attraction preference of S. frugiperda larvae on these maize varieties, using an olfactometer bioassay. We found that S. frugiperda females oviposited significantly less egg masses on the hybrid varieties DEKAIB and 30Y87 than on the other varieties tested, and that females oviposited less on the hybrid maize varieties compared to the open pollinated maize varieties overall. Additionally, we found that S. frugiperda larvae were more attracted to the open pollinated variety LMFP than to clean air, which was not the case for any of the other maize varieties tested. Taken together, our results show that S. frugiperda responds differentially to the different maize varieties and that hybrid maize varieties seem less attractive. Further investigating the chemistry of hybrid maize varieties like DEKAIB might yield clues on how to breed maize varieties with increased resistance against S. frugiperda infestation.

Several evolutionary explanations for multiple mating in insects have been proposed, and it has been suggested that Lepidoptera benefit from the energy contained in nuptial gifts. In two closely related species of small ermine moths, Yponomeuta cagnagellus (Hübner) and Yponomeuta padellus (L.), we experimentally controlled the number of matings and access to honey as an energy source, and assessed the effects of these factors on female life span and lifetime fecundity. No positive effects of mating were found in either species. In fact, mating significantly shortened life span. The effect of access to energy in the form of honey differed between the two species. In the shorter-lived Yponomeuta padellus, access to honey did not increase the life span of mated females and did not increase fecundity. In Yponomeuta cagnagellus however, access to energy in the form of honey counteracted the negative effects of mating and females with access to honey lived significantly longer and laid significantly more eggs during their lifetime.

Global crises, such as climate change and ecological collapse, require changes in systemic factors that cause the crises. These factors include the economy, population growth, and decision-making in global affairs. Current decision-making processes have failed to accomplish the required system change, necessitating a change to these processes (‘decision change’) for meaningful progress. The key question is how a procedure for deciding on the required system change should be designed in this setting. In this essay, we propose a three-step approach. First, independent experts in collective decision-making should design this procedure under monitoring by auxiliary bodies that safeguard the design process; second, proposals for system change should be collected; third, based on these proposals, system change should be designed and decided upon using the new decision-making procedure. We argue that authority can be given to the new decision-making body that decides on system change. A global team must convene the decision-making experts and auxiliary bodies, collect system-change proposals, and guarantee that the decision-making process is facilitated. We call on individuals and independent organisations to form such a team or support its formation.

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a global pest that feeds on > 350 plant species and causes major yield loses. Variation in the responses of S. frugiperda males to female sex pheromone compounds affects the detection, monitoring and management of the pest. We determined geographic variation in the responses of S. frugiperda males to four different doses of synthetic sex pheromone compounds using a gas chromatography-electroantennogram detector (GC-EAD). Furthermore, we disentangled regional populations into C- and R- mitotypes via molecular analysis of the cytochrome oxidase I gene, and measured their responses to the compounds. When comparing responses of males from Florida, Benin, Nigeria and Kenya, we found some regional differences in the responses of S. frugiperda males to the major compound, Z9-14:OAc and minor component Z9-12:OAc. However, we found no differences in male responses between the different African countries. All males showed significantly higher antennal responses to Z7-12:OAc than to E7-12:OAc. When comparing the mitotypes, we found that Florida R-type males showed higher responses to Z9-14:OAc, Z7-12:OAc and Z9-12:OAc than Benin R-type males, while C-type males from both regions responded equally to Z7-12:OAc. In addition, Florida R-type males showed higher responses to E7-12:OAc than Florida C-type males. Our study thus shows some differential physiological responses of S. frugiperda males towards the known sex pheromone compounds, including E7-12:OAc, but mostly in the different mitotypes. How these differences translate to field trap catches remains to be determined.

Phytophagous insects likely select suitable host plants for oviposition based on olfactory and tactile cues. However, details of how insects differentiate among different plant varieties are often unclear. The fall armyworm (Spodoptera frugiperda J. E. Smith) is a highly destructive pest on maize, but little is known about the attraction and oviposition preference of S. frugiperda to different maize varieties, particularly in the context of sub-Saharan Africa, where the insect is a major threat to maize production. We determined the oviposition preference of S. frugiperda females on six different maize plant varieties three of which were hybrid varieties and three were open-pollinated varieties, in multiple-choice and no-choice assays. We also evaluated the attraction preference of S. frugiperda larvae on these maize varieties, using an olfactometer bioassay. We found that S. frugiperda females oviposited significantly less egg masses on the hybrid varieties DEKAIB and 30Y87 than on the other varieties tested and that females oviposited less on the hybrid maize varieties compared to the open-pollinated maize varieties overall. Additionally, we found that S. frugiperda larvae were more attracted to the open-pollinated variety LMFP than to clean air, which was not the case for any of the other maize varieties tested. Taken together, our results show that S. frugiperda responds differentially to the different maize varieties and that hybrid maize varieties seem less attractive. Further investigating the chemistry of hybrid maize varieties like DEKAIB might yield clues on how to breed maize varieties with increased resistance against S. frugiperda infestation.

In order to achieve a better understanding of the factors that might have led our hominin ancestors to transition to a more terrestrial niche, including sleeping on the ground, we have conducted a study on the ground nesting behavior of chimpanzees (Pan troglodytes). Chimpanzees, like all other species of great apes, build nests in which to sleep each night, but little is known about regional differences in their nesting habits. Previously, nesting on the ground was considered typical of gorillas, but rare in most populations of chimpanzees. Using data acquired during our extensive chimpanzee nesting survey conducted between 2004 and 2013 across a > 50 000 km2 region in northern Democratic Republic of the Congo, we report a distinctive ground nesting behaviour of eastern chimpanzees (P. t. schweinfurthii). We have mapped the geographical distribution of ground nesting and compared its frequency at 20 survey areas on both sides of a large river, the Uele. We found that ground nests made up more than 1% of total nests at 15 of the 20 survey regions. For a subset of 16 of these regions, we utilized statistical models to investigate whether forest type and structure, as well as the abundance of carnivores and large herbivores, and the activities of humans impacted the frequency of ground nesting and nest height. We predicted that higher encounter rates of human and dangerous animal signs would be associated with lower rates of ground nesting as well as increased nest height. Overall, 10.4% of the Bili-Uéré chimpanzee nests were terrestrial, but the frequency of ground nesting varied extensively between the survey areas (0-29% of nests). The occurrence of ground nests was positively associated with denser forests (p = 0.004), herb patches (p < 0.001), and light gaps (p < 0.001). Light gaps (p < 0.001), herb patches (p = 0.044), and vine tangles (p = 0.016) also had a strong negative effect on nest height. Hunting by humans had a negative effect on the probability of the occurrence of ground nests (p = 0.001) and a positive one on nest height (p = 0.013), with a similar but likely marginal effect of large herbivores on nest height (p = 0.023). In addition, the chimpanzees nested at significantly lower heights with increasing distance from roads and settlements (p < 0.001). Carnivore encounter rates, however, had no significant impact on ground nest frequency or nest height. Our results indicate that ground nesting can no longer be considered a rare and patchily-occurring phenomenon in Pan troglodytes, but is instead a major component of the chimpanzee behavioural repertoire across a considerable fraction of the range of the Eastern subspecies. Our study highlights that neither the large body size of gorillas nor the taming of fire are necessary conditions for hominids to sleep overnight on the ground, even in areas inhabited by multiple species of large carnivore. Human hunting, however, appears to reduce the probability of ground nesting, or eliminate the behavior altogether.

Sex chromosome-autosome fusions give rise to neo-sex chromosomes, which provide an insight into early evolution of sex chromosomes and drivers of chromosomal fusions. While sex chromosome-autosome fusions are scarce in vertebrates with female heterogamety (♀ZW/♂ZZ), they are common in moths and butterflies (Lepidoptera), the most species rich group with heterogametic females. This contradicts theoretical model that assumes chromosome fusions to be random and predicts them to be rare in taxa with high chromosome number such as Lepidoptera. In the present study we analyzed sex chromosomes in nine ermine moths of the genus Yponomeuta (Yponomeutidae) and their two outgroups, Teinoptila gutella (Yponomeutidae) and Plutella xylostella (Plutellidae). We employed genomic in situ hybridization to identify sex chromosomes and used a custom designed microarray to identify Z-linked genes. Our results confirmed a multiple sex chromosome system Z1Z2W to be present in T. gutella and all Yponomeuta spp. except for Y. tokyonella . The multiple sex chromosome system resulted from a fusion between the W chromosome and autosome homeologous to the Bombyx mori chromosome 2 (BmChr2). The BmChr2 bears a cluster of genes with ovary-specific expression which suggests that sexually antagonistic selection could have driven fixation of the fusion in a common ancestor of Yponomeuta and Teinoptila genera. We hypothesize that sex chromosome turnover in Lepidoptera could be driven by sexual antagonism.

Many lepidopteran species produce silk, cocoons, feeding tubes, or nests for protection from predators and parasites for caterpillars and pupae. Yet, the number of lepidopteran species whose silk composition has been studied in detail is very small, because the genes encoding the major structural silk proteins tend to be large and repetitive, making their assembly and sequence analysis difficult. Here we have analyzed the silk of Yponomeuta cagnagella, which represents one of the early diverging lineages of the ditrysian Lepidoptera thus improving the coverage of the order. To obtain a comprehensive list of the Y. cagnagella silk genes, we sequenced and assembled a draft genome using Oxford Nanopore and Illumina technologies. We used a silk-gland transcriptome and a silk proteome to identify major silk components and verified the tissue specificity of expression of individual genes. A detailed annotation of the major genes and their putative products, including their complete sequences and exon-intron structures is provided. The morphology of silk glands and fibers are also shown. This study fills an important gap in our growing understanding of the structure, evolution, and function of silk genes and provides genomic resources for future studies of the chemical ecology of Yponomeuta species.

Shelled pteropods are widely regarded as bioindicators for ocean acidification, because their fragile aragonite shells are susceptible to increasing ocean acidity. While short-term incubations have demonstrated that pteropod calcification is negatively impacted by ocean acidification, we know little about net calcification in response to varying ocean conditions in natural populations. Here, we examine in situ calcification of Limacina helicina pteropods collected from the California Current Ecosystem, a coastal upwelling system with strong spatial gradients in ocean carbonate chemistry, dissolved oxygen and temperature. Depth-averaged pH ranged from 8.03 in warmer offshore waters to 7.77 in cold CO 2 -rich waters nearshore. Based on high-resolution micro-CT technology, we showed that shell thickness declined by ~ 37% along the upwelling gradient from offshore to nearshore water. Dissolution marks covered only ~ 2% of the shell surface area and were not associated with the observed variation in shell thickness. We thus infer that pteropods make thinner shells where upwelling brings more acidified and colder waters to the surface. Probably the thinner shells do not result from enhanced dissolution, but are due to a decline in calcification. Reduced calcification of pteropods is likely to have major ecological and biogeochemical implications for the cycling of calcium carbonate in the oceans.

The original version of this article unfortunately contained mistakes in the Discussion and Acknowledgments sections. The changes are shown below:

The aim of this study was to validate a workflow that allows structural identification of plant volatiles that induce a behavioral response in insects. Due to the complexity of plant volatile emissions and the low levels at which these bioactive components tend to occur, gas chromatography-electroantennography (GC-EAD) was applied as the prime differentiator technique, i.e., to indicate particular peaks of interest in the chromatogram. In a next step, the analysis was repeated under identical conditions using GC-Orbitrap mass spectrometry (MS). Combining electron impact (EI) ionization and chemical ionization (CI) with the superior spectral resolution and mass accuracy of the technique enabled straightforward identification of these unknowns, with high confidence in a minute amount of time. Moreover, because of the intrinsic sensitivity of the technique, components that occur at trace amounts but may induce disproportional large behavioral responses are evenly well-identified. We were able to positively identify β-caryophyllene as a bioactive compound in female carob moths. Behavioral attraction was negatively correlated with the amount of β-caryophyllene in host fruits. In an oviposition experiment on filter paper, β-caryophyllene was stimulated in the range of 40–100 ng, while concentrations above 200 ng inhibited oviposition.

In evolutionarily young species and sympatric host races of phytophagous insects, postzygotic incompatibility is often not yet fully developed, but reduced fitness of hybrids is thought to facilitate further divergence. However, empirical evidence supporting this hypothesis is limited. To assess the role of reduced hybrid fitness, we studied meiosis and fertility in hybrids of two closely related small ermine moths, Yponomeuta padella and Yponomeuta cagnagella, and determined the extent of intrinsic postzygotic reproductive isolation. We found extensive rearrangements between the karyotypes of the two species and irregularities in meiotic chromosome pairing in their hybrids. The fertility of reciprocal F1 and, surprisingly, also of backcrosses with both parental species was not significantly decreased compared with intraspecific offspring. The results indicate that intrinsic postzygotic reproductive isolation between these closely related species is limited. We conclude that the observed chromosomal rearrangements are probably not the result of an accumulation of postzygotic incompatibilities preventing hybridization. Alternative explanations, such as adaptation to new host plants, are discussed.

To improve our understanding of the evolutionary origins of culture and technology in humans, it is vital that we document the full extent of behavioural diversity in our great ape relatives. About half of the world’s remaining chimpanzees (Pan spp.) live in the Democratic Republic of Congo (DRC), yet until now we have known almost nothing about their behaviour. Here we describe the insect-related tool technology of Bili-Uéré chimpanzees (Pan troglodytes schweinfurthii) inhabiting an area of at least a 50,000-km2 area in northern DRC, as well as their percussive technology associated with food processing. Over a 12-year period, we documented chimpanzee tools and artefacts at 20 survey areas and gathered data on dung, feeding remains and sleeping nests. We describe a new chimpanzee tool kit: long probes used to harvest epigaeic driver ants (Dorylus spp.), short probes used to extract ponerine ants and the arboreal nests of stingless bees, wands to dip for D. kohli and stout digging sticks used to access underground meliponine bee nests. Epigaeic Dorylus tools were significantly longer than the other tool types, and D. kohli tools were significantly thinner. Tools classified as terrestrial honey-digging sticks were a significant predictor for brushed and blunted tool ends, consistent with their presumed use. We describe two potential new tool types, an “ant scoop” and a “fruit hammer.” We document an extensive percussive technology used to process termite mounds of Cubitermes sp. and Thoracotermes macrothorax and hard-shelled fruits such as Strychnos, along with evidence of the pounding open of African giant snails and tortoises. We encountered some geographic variation in behaviour: we found honey-digging tools, long driver ant probes and fruit-pounding sites only to the north of the Uele River; there were more epigaeic Dorylus tools to the north and more ponerine ant tools to the south. We found no evidence of termite-fishing, despite the availability of Macrotermes muelleri mounds throughout the region. This lack of evidence is consistent with the results of dung washes, which revealed a substantial proportion of driver ants, but no evidence of Macrotermes or other termites. Our results allow us to describe a new chimpanzee behavioural complex, characterised by a general similarity of multiple behaviours across a large, ecologically diverse region but with subtle differences in prey choice and techniques. We propose that this widespread and related suite of behaviours be referred to as the Bili-Uéré Chimpanzee Behavioural Realm. Possible explanations for this pattern are a recent chimpanzee expansion across the region and the interconnectedness of this population across at least the entirety of northern DRC.

The carob moth, Ectomyelois ceratoniae (Zeller; Lepidoptera: Pyralidae), is a devastating pest in high-value crops around the world. An efficient sex pheromone attractant is still missing for the management of this pest, because the major pheromone component is unstable. Host plant volatiles attract herbivore insects and have shown to have good potential to be exploited as alternatives or supplements to sex pheromones. To explore this possibility in carob moth, we assessed the attraction of moths to the volatiles of mature pistachio and different fruit stages of pomegranate, alone and in combination with virgin females, using sticky delta traps in pomegranate orchards of Iran. Traps baited with mature pomegranates, whether uncracked or cracked, infested or uninfested, caught significantly larger numbers of male and both mated and virgin female carob moths than unbaited traps. Traps baited with headspace extract of cracked pomegranate only caught mated females, while mature pistachio only attracted males. Pomegranate flowers, unripe pomegranate, and headspace extract of pistachio did not attract moths. Traps baited with cracked fruit caught more mated females than traps baited with uncracked fruit. Males were attracted similarly to traps baited with cracked-infested pomegranate as to traps baited with virgin females alone. Interestingly, the combination of cracked pomegranate and virgin female enhanced the attraction of virgin females. Together, our results show that volatiles from cracked pomegranates alone or in combination with female sex pheromone have great potential for application in pest management programs of carob moth.

Increasing surface temperatures, Arctic sea-ice loss, and other evidence of anthropogenic global warming (AGW) are acknowledged by every major scientific organization in the world. However, there is a wide gap between this broad scientific consensus and public opinion. Internet blogs have strongly contributed to this consensus gap by fomenting misunderstandings of AGW causes and consequences. Polar bears (Ursus maritimus) have become a "poster species" for AGW, making them a target of those denying AGW evidence. Here, focusing on Arctic sea ice and polar bears, we show that blogs that deny or downplay AGW disregard the overwhelming scientific evidence of Arctic sea-ice loss and polar bear vulnerability. By denying the impacts of AGW on polar bears, bloggers aim to cast doubt on other established ecological consequences of AGW, aggravating the consensus gap. To counter misinformation and reduce this gap, scientists should directly engage the public in the media and blogosphere.