Evo-devo of wing colour patterns in beetles.

Insects have evolved tremendously diverse wing colour patterns that fulfil ecologically vital functions, including intraspecific sexual signalling, mimesis, mimicry, and detering predators. Beetles, which form the most species-rich order Coleoptera, have amazingly diverse wing colour patterns; however, the molecular mechanisms that give rise to these patterns remain poorly understood. Recently, the gene pannier (pnr), which encodes a transcription factor of the GATA family, was identified as an essential player in the wing patterning of the multi-coloured Asian ladybird beetle Harmonia axyridis.

Nanopore Formation in the Cuticle of an Insect Olfactory Sensillum.

Nanometer-level patterned surface structures form the basis of biological functions, including superhydrophobicity, structural coloration, and light absorption [1-3]. In insects, the cuticle overlying the olfactory sensilla has multiple small (50- to 200-nm diameter) pores [4-8], which are supposed to function as a filter that admits odorant molecules, while preventing the entry of larger airborne particles and limiting water loss. However, the cellular processes underlying the patterning of extracellular matrices into functional nano-structures remain unknown.

Precise staging of beetle horn formation in Trypoxylus dichotomus reveals the pleiotropic roles of doublesex depending on the spatiotemporal developmental contexts.

Many scarab beetles have sexually dimorphic exaggerated horns that are an evolutionary novelty. Since the shape, number, size, and location of horns are highly diverged within Scarabaeidae, beetle horns are an attractive model for studying the evolution of sexually dimorphic and novel traits. In beetles including the Japanese rhinoceros beetle Trypoxylus dichotomus, the sex differentiation gene doublesex (dsx) plays a crucial role in sexually dimorphic horn formation during larval-pupal development.

Development and evolution of color patterns in ladybird beetles: A case study in Harmonia axyridis.

Many organisms show various geometric color patterns on their bodies, and the developmental, evolutionary, genetic, and ecological bases of these patterns have been intensely studied in various organisms. Ladybird beetles display highly diverse patterns of wing (elytral) color and are one of the most attractive model organisms for studying these characteristics. In this study, we reviewed the genetic history of elytral color patterns in the Asian multicolored ladybird beetle Harmonia axyridis from the classical genetic studies led by the pupils of Thomas Hunt Morgan and Theodosius Dobzhansky to recent genomic studies that revealed that a single GATA transcription factor gene, pannier, regulates the highly diverse elytral color patterns in this species.

Repeated inversions within a pannier intron drive diversification of intraspecific colour patterns of ladybird beetles.

How genetic information is modified to generate phenotypic variation within a species is one of the central questions in evolutionary biology. Here we focus on the striking intraspecific diversity of >200 aposematic elytral (forewing) colour patterns of the multicoloured Asian ladybird beetle, Harmonia axyridis, which is regulated by a tightly linked genetic locus h. Our loss-of-function analyses, genetic association studies, de novo genome assemblies, and gene expression data reveal that the GATA transcription factor gene pannier is the major regulatory gene located at the h locus, and suggest that repeated inversions and cis-regulatory modifications at pannier led to the expansion of colour pattern variation in H.

The pivotal role of aristaless in development and evolution of diverse antennal morphologies in moths and butterflies.

Background: Antennae are multi-segmented appendages and main odor-sensing organs in insects. In Lepidoptera (moths and butterflies), antennal morphologies have diversified according to their ecological requirements. While diurnal butterflies have simple, rod-shaped antennae, nocturnal moths have antennae with protrusions or lateral branches on each antennal segment for high-sensitive pheromone detection.

Toll ligand Spätzle3 controls melanization in the stripe pattern formation in caterpillars.

A stripe pattern is an aposematic or camouflage coloration often observed among various caterpillars. However, how this ecologically important pattern is formed is largely unknown. The silkworm dominant mutant () has a black stripe in the anterior margin of each dorsal segment.

A genetic mechanism for female-limited Batesian mimicry in Papilio butterfly.

In Batesian mimicry, animals avoid predation by resembling distasteful models. In the swallowtail butterfly Papilio polytes, only mimetic-form females resemble the unpalatable butterfly Pachliopta aristolochiae. A recent report showed that a single gene, doublesex (dsx), controls this mimicry; however, the detailed molecular mechanisms remain unclear.

Periodic Wnt1 expression in response to ecdysteroid generates twin-spot markings on caterpillars.

Among various pigmentation patterns on caterpillars, sequential spot markings are often observed and used for aposematic colouration. In contrast to adult wings, caterpillar cuticle markings are repeatedly generated at each moult, but little is known about how the patterns are formed and maintained periodically. Here we focus on a silkworm mutant, multi lunar (L), with twin-spot markings on sequential segments.

Electroporation-mediated somatic transgenesis for rapid functional analysis in insects.

Transgenesis is a powerful technique for determining gene function; however, it is time-consuming. It is virtually impossible to carry out in non-model insects in which egg manipulation and screening are difficult. We have established a rapid genetic functional analysis system for non-model insects using a low-cost electroporator (costing under US$200) designed for somatic transformation with the piggyBac transposon.

Dramatic changes in patterning gene expression during metamorphosis are associated with the formation of a feather-like antenna by the silk moth, Bombyx mori.

Many moths use sex pheromones to find their mates in the dark. Their antennae are well developed with lateral branches to receive the pheromone efficiently. However, how these structures have evolved remains elusive, because the mechanism of development of these antennae has not been studied at a molecular level.

In vivo gene transfer into the honeybee using a nucleopolyhedrovirus vector.

The honeybee Apis mellifera L. is a social insect and one of the most industrially important insects. We examined whether a baculovirus-mediated retrotransposon is applicable to in vivo transfer of exogenous genes to the honeybees.