On the basis of an assemblage of fossilized wing scales recovered from latest Triassic and earliest Jurassic sediments from northern Germany, we provide the earliest evidence for Lepidoptera (moths and butterflies). The diverse scales confirm a (Late) Triassic radiation of lepidopteran lineages, including the divergence of the Glossata, the clade that comprises the vast multitude of extant moths and butterflies that have a sucking proboscis. The microfossils extend the minimum calibrated age of glossatan moths by ca. 70 million years, refuting ancestral association of the group with flowering plants. Development of the proboscis may be regarded as an adaptive innovation to sucking free liquids for maintaining the insect’s water balance under arid conditions. Pollination drops secreted by a variety of Mesozoic gymnosperms may have been non-mutualistically exploited as a high-energy liquid source. The early evolution of the Lepidoptera was probably not severely interrupted by the end-Triassic biotic crisis.
The role of bats or any generalist predator in suppressing prey populations depends on the predator’s ability to track and exploit available prey. Using a qPCR fecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis) consuming corn earworm (CEW) moths (Helicoverpa zea) and seasonal fluctuations in CEW populations. This result is consistent with earlier research linking the bats' diet to patterns of migration, abundance, and crop infestation by important insect pests. Here we confirm opportunistic feeding on one of the world’s most destructive insects and support model estimates of the bats' ecosystem services. Regression analysis of CEW consumption versus the moth’s abundance at four insect trapping sites further indicates that bats track local abundance of CEW within the regional landscape. Estimates of CEW gene copies in the feces of bats are not associated with seasonal or local patterns of CEW abundance, and results of captive feeding experiments indicate that our qPCR assay does not provide a direct measure of numbers or biomass of prey consumed. Our results support growing evidence for the role of generalist predators, and bats specifically, as agents for biological control and speak to the value of conserving indigenous generalist predators.
Boric acid is widely used as an insecticide, acaricide, herbicide, and fungicide and also during various industrial processings. Hence, numerous populations are subjects to this toxic compound. Its action on animals is still not fully known and understood. We examined the effect of boric acid on larvae of greater wax moth (Galleria mellonella). The chemical appeared to be toxic for larvae, usually in a concentration-dependent manner. Exposed groups revealed increased lipid peroxidation and altered activity of catalase, superoxide dismutase, glutathione S-transferase, and glutathione peroxidase. We also observed changes of ultrastructure, which were in tune with biochemical assays. We suggest that boric acid has a broad mode of action, which may affect exposed larvae, and even if sublethal, they may lead to disturbances within exposed populations.
Plastics are synthetic polymers derived from fossil oil and largely resistant to biodegradation. Polyethylene (PE) and polypropylene (PP) represent ∼92% of total plastic production. PE is largely utilized in packaging, representing ∼40% of total demand for plastic products (www.plasticseurope.org) with over a trillion plastic bags used every year . Plastic production has increased exponentially in the past 50 years (Figure S1A in Supplemental Information, published with this article online). In the 27 EU countries plus Norway and Switzerland up to 38% of plastic is discarded in landfills, with the rest utilized for recycling (26%) and energy recovery (36%) via combustion (www.plasticseurope.org), carrying a heavy environmental impact. Therefore, new solutions for plastic degradation are urgently needed. We report the fast bio-degradation of PE by larvae of the wax moth Galleria mellonella, producing ethylene glycol.
Camouflage, and in particular background-matching, is one of the most common anti-predator strategies observed in nature. Animals can improve their match to the colour/pattern of their surroundings through background selection, and/or by plastic colour change. Colour change can occur rapidly (a few seconds), or it may be slow, taking hours to days. Many studies have explored the cues and mechanisms behind rapid colour change, but there is a considerable lack of information about slow colour change in the context of predation: the cues that initiate it, and the range of phenotypes that are produced. Here we show that peppered moth (Biston betularia) larvae respond to colour and luminance of the twigs they rest on, and exhibit a continuous reaction norm of phenotypes. When presented with a heterogeneous environment of mixed twig colours, individual larvae specialise crypsis towards one colour rather than developing an intermediate colour. Flexible colour change in this species has likely evolved in association with wind dispersal and polyphagy, which result in caterpillars settling and feeding in a diverse range of visual environments. This is the first example of visually induced slow colour change in Lepidoptera that has been objectively quantified and measured from the visual perspective of natural predators.
- Proceedings of the National Academy of Sciences of the United States of America
- Published over 5 years ago
Nipple-like nanostructures covering the corneal surfaces of moths, butterflies, and Drosophila have been studied by electron and atomic force microscopy, and their antireflective properties have been described. In contrast, corneal nanostructures of the majority of other insect orders have either been unexamined or examined by methods that did not allow precise morphological characterization. Here we provide a comprehensive analysis of corneal surfaces in 23 insect orders, revealing a rich diversity of insect corneal nanocoatings. These nanocoatings are categorized into four major morphological patterns and various transitions between them, many, to our knowledge, never described before. Remarkably, this unexpectedly diverse range of the corneal nanostructures replicates the complete set of Turing patterns, thus likely being a result of processes similar to those modeled by Alan Turing in his famous reaction-diffusion system. These findings reveal a beautiful diversity of insect corneal nanostructures and shed light on their molecular origin and evolutionary diversification. They may also be the first-ever biological example of Turing nanopatterns.
An evolutionary war is being played out between the bat, which uses ultrasonic calls to locate insect prey, and the moth, which uses microscale ears to listen for the approaching bat. While the highest known frequency of bat echolocation calls is 212 kHz, the upper limit of moth hearing is considered much lower. Here, we show that the greater wax moth, Galleria mellonella, is capable of hearing ultrasonic frequencies approaching 300 kHz; the highest frequency sensitivity of any animal. With auditory frequency sensitivity that is unprecedented in the animal kingdom, the greater wax moth is ready and armed for any echolocation call adaptations made by the bat in the on-going bat-moth evolutionary war.
The life-like fidelity of organisms captured in amber is unique among all kinds of fossilization and represents an invaluable source for different fields of palaeontological and biological research. One of the most challenging aspects in amber research is the study of traits related to behaviour. Here, indirect evidence for pheromone-mediated mating behaviour is recorded from a biting midge (Ceratopogonidae) in 54 million-year-old Indian amber. Camptopterohelea odora n. sp. exhibits a complex, pocket shaped structure on the wings, which resembles the wing folds of certain moth flies (Diptera: Psychodidae) and scent organs that are only known from butterflies and moths (Lepidoptera) so far. Our studies suggests that pheromone releasing structures on the wings have evolved independently in biting midges and might be much more widespread in fossil as well as modern insects than known so far.
From the outset multiple causes have been suggested for changes in melanic gene frequency in the peppered moth Biston betularia and other industrial melanic moths. These have included higher intrinsic fitness of melanic forms and selective predation for camouflage. The possible existence and origin of heterozygote advantage has been debated. From the 1950s, as a result of experimental evidence, selective predation became the favoured explanation and is undoubtedly the major factor driving the frequency change. However, modelling and monitoring of declining melanic frequencies since the 1970s indicate either that migration rates are much higher than existing direct estimates suggested or else, or in addition, non-visual selection has a role. Recent molecular work on genetics has revealed that the melanic (carbonaria) allele had a single origin in Britain, and that the locus is orthologous to a major wing patterning locus in Heliconius butterflies. New methods of analysis should supply further information on the melanic system and on migration that will complete our understanding of this important example of rapid evolution.Heredity advance online publication, 5 December 2012; doi:10.1038/hdy.2012.92.
Discovering the mutational events that fuel adaptation to environmental change remains an important challenge for evolutionary biology. The classroom example of a visible evolutionary response is industrial melanism in the peppered moth (Biston betularia): the replacement, during the Industrial Revolution, of the common pale typica form by a previously unknown black (carbonaria) form, driven by the interaction between bird predation and coal pollution. The carbonaria locus has been coarsely localized to a 200-kilobase region, but the specific identity and nature of the sequence difference controlling the carbonaria-typica polymorphism, and the gene it influences, are unknown. Here we show that the mutation event giving rise to industrial melanism in Britain was the insertion of a large, tandemly repeated, transposable element into the first intron of the gene cortex. Statistical inference based on the distribution of recombined carbonaria haplotypes indicates that this transposition event occurred around 1819, consistent with the historical record. We have begun to dissect the mode of action of the carbonaria transposable element by showing that it increases the abundance of a cortex transcript, the protein product of which plays an important role in cell-cycle regulation, during early wing disc development. Our findings fill a substantial knowledge gap in the iconic example of microevolutionary change, adding a further layer of insight into the mechanism of adaptation in response to natural selection. The discovery that the mutation itself is a transposable element will stimulate further debate about the importance of ‘jumping genes’ as a source of major phenotypic novelty.