Region-Specific Variation in the Electrophysiological Responses of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Synthetic Sex Pheromone Compounds.

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.

Factors affecting nest height and ground nesting behaviour in Eastern chimpanzees (Pan troglodytes schweinfurthii) of the northern Democratic Republic of the Congo.

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.

Bili-Uéré: A Chimpanzee Behavioural Realm in Northern Democratic Republic of Congo.

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.

Corrigendum: Internet Blogs, Polar Bears, and Climate-Change Denial by Proxy.

[This corrects the article DOI: 10.1093/biosci/bix133.].

Internet Blogs, Polar Bears, and Climate-Change Denial by Proxy.

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.

Pollination of Specklinia by nectar-feeding Drosophila: the first reported case of a deceptive syndrome employing aggregation pheromones in Orchidaceae.

BACKGROUND AND AIMS: The first documented observation of pollination in Pleurothallidinae was that of Endrés, who noticed that the 'viscid sepals' of Specklinia endotrachys were visited by a 'small fly'. Chase would later identify the visiting flies as being members of the genus Drosophila. This study documents and describes how species of the S. endotrachys complex are pollinated by different Drosophila species. METHODS: Specimens of Specklinia and Drosophila were collected in the field in Costa Rica and preserved in the JBL and L herbaria. Flies were photographed, filmed and observed for several days during a 2-year period and were identified by a combination of non-invasive DNA barcoding and anatomical surveys. Tissue samples of the sepals, petals and labellum of Specklinia species were observed and documented by SEM, LM and TEM. Electroantennogram experiments were carried out on Drosophila hydei using the known aggregation pheromones ethyl tiglate, methyl tiglate and isopropyl tiglate. Floral compounds were analysed by gas chromatography-mass spectometry using those same pheromones as standards. KEY RESULTS: Flowers of S. endotrachys, S. pfavii, S. remotiflora and S. spectabilis are visited and pollinated by several different but closely related Drosophila species. The flies are arrested by aggregation pheromones, including ethyl tiglate, methyl tiglate and isopropyl tiglate, released by the flowers, and to which at least D. hydei is very sensitive. Visible nectar drops on the adaxial surface of sepals are secreted by nectar-secreting stomata, encouraging male and female Drosophila to linger on the flowers for several hours at a time. The flies frequently show courtship behaviour, occasionally copulating. Several different Drosophila species can be found on a single Specklinia species. CONCLUSIONS: Species of the S. endotrachys group share a similar pollination syndrome. There seem to be no species-specific relationships between the orchids and the flies. It is not expected that Specklinia species will hybridize naturally as their populations do not overlap geographically. The combination of pheromone attraction and nectar feeding is likely to be a generalized pollination syndrome in Pleurothallidinae.

Impact of humans on long-distance communication behaviour of eastern chimpanzees (Pan troglodytes schweinfurthii) in the Northern Democratic Republic of the Congo.

We systematically recorded all long-distance chimpanzee vocalizations and tree drums over a 26-month study period in 13 forest regions in the Democratic Republic of the Congo. We found that the frequency of chimpanzee vocalizations and tree drums was considerably higher in the remote Gangu Forest than in other forest regions closer to human settlements and roads. We present evidence indicating that chimpanzees may reduce their levels of vocalizations in areas characterized by high levels of human hunting. The chimpanzees appear to have the behavioural flexibility necessary to modify their behaviour in areas where humans are a major threat. We discuss the possible consequences of this reduction in vocalization rate on the social system of the chimpanzees.

Reactions of Bili-Uele chimpanzees to humans in relation to their distance from roads and villages.

In order to assess the impact of human activities on chimpanzee behavior, we compared reactions to humans of Eastern chimpanzees (Pan troglodytes schweinfurthii) living in proximity to and at a distance from roads and settlements in the Bili-Uele landscape in Northern Democratic Republic of the Congo (DRC). We found that chimpanzees in the remote Gangu Forest were more likely to show curious or neutral reactions to us and were less likely to flee than those living closer to roads. In addition, arboreal contact durations with Gangu chimpanzees lasted significantly longer than elsewhere. The most likely explanation for this phenomenon is that with increasing distance from roads, chimpanzees have in the recent past had fewer negative encounters with humans, and thus never learned to fear them. The discovery of this population of "naïve chimpanzees" presents us with an important research and conservation opportunity that may result in the installation of a long-term research site and increased protection of the population.

Genome sequence and silkomics of the spindle ermine moth, Yponomeuta cagnagella, representing the early diverging lineage of the ditrysian Lepidoptera.

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.

Pteropods make thinner shells in the upwelling region of the California Current Ecosystem.

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 CO2-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.

Field Attraction of Carob Moth to Host Plants and Conspecific Females.

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.

Olfactory receptors on the maxillary palps of small ermine moth larvae: evolutionary history of benzaldehyde sensitivity.

In lepidopterous larvae the maxillary palps contain a large portion of the sensory equipment of the insect. Yet, knowledge about the sensitivity of these cells is limited. In this paper a morphological, behavioral, and electrophysiological investigation of the maxillary palps of Yponomeuta cagnagellus (Lepidoptera: Yponomeutidae) is presented. In addition to thermoreceptors, CO(2) receptors, and gustatory receptors, evidence is reported for the existence of two groups of receptor cells sensitive to plant volatiles. Cells that are mainly sensitive to (E)-2-hexenal and hexanal or to (Z)-3-hexen-1-ol and 1-hexanol were found. Interestingly, a high sensitivity for benzaldehyde was also found. This compound is not known to be present in Euonymus europaeus, the host plant of the monophagous Yponomeuta cagnagellus, but it is a prominent compound in Rosaceae, the presumed hosts of the ancestors of Y. cagnagellus. To elucidate the evolutionary history of this sensitivity, and its possible role in host shifts, feeding responses of three Yponomeuta species to benzaldehyde were investigated. The results confirm the hypothesis that the sensitivity to benzaldehyde evolved during the ancestral shift from Celastraceae to Rosaceae and can be considered an evolutionary relict, retained in the recently backshifted Celastraceae-specialist Y. cagnagellus.

State-dependent and odour-mediated anemotactic responses of the predatory mite Phytoseiulus persimilis in a wind tunnel.

Anemotaxis in the predatory mite Phytoseiulus persimilis (both well-fed and starved), has previously been studied on a wire grid under slight turbulent airflow conditions yielding weak, yet distinct, gradients in wind speed and odour concentration (Sabelis and Van der Weel 1993). Such conditions might have critically influenced the outcome of the study. We repeated these experiments, under laminar airflow conditions on a flat surface in a wind tunnel, thereby avoiding variation in wind speed and odour concentration. Treatments for starved and well-fed mites were (1) still-air without herbivore-induced plant volatiles (HIPV) (well-fed mites only), (2) an HIPV-free air stream, and (3) an air stream with HIPV (originating from Lima bean plants infested by two-spotted spider mites, Tetranychus urticae). Well-fed mites oriented in random directions in still-air without HIPV. In an air stream, starved mites always oriented upwind, whether plant odours were present or not. Well-fed mites oriented downwind in an HIPV-free air stream, but in random directions in an air stream with HIPV. Only under the last treatment our results differed from those of Sabelis and Van der Weel (1993).

State-dependent and odor-mediated anemotactic responses of a micro-arthropod on a novel type of locomotion compensator.

A novel type of locomotion compensator was designed and tested for its use in orientation behavior experiments with a predatory mite. In this apparatus, displacements of the test animal in the two-dimensional plane are recorded using video equipment and a servosphere that keeps the animal in focus. The x and y displacements are registered using two rotation encoders and are compensated using a pair of servo-motors, in such a way that the animal is always positioned on top of the sphere, yet moves freely. Well-fed and starved predators were tested for their responses to (1) still air, (2) a stimulus-free air flow, (3) an air flow with odors from uninfested Lima bean leaves, and (4) an air flow with odors from Lima bean leaves infested by plant-feeding mites, the prey of the predatory mites. Anemotactic responses of adult Phytoseiulus persimilis females were feeding state dependent. Well-fed predators moved downwind under Treatments 1-3 but moved neither up- nor downwind in the presence of odors from infested plants (Treatment 4). Starved predators moved upwind under all treatments. These results are in agreement with those of earlier studies in a wind tunnel, and therefore, the new type of locomotion compensator (LC-100) offers an excellent method for studying the orientation behavior of micro-arthropods.