Ancient developmental genes underlie evolutionary novelties in walking fish.

A critical question in biology is how new traits evolve, but studying this in wild animals remains challenging. Here, we probe the genetic basis of trait gain in sea robin fish, which have evolved specialized leg-like appendages for locomotion and digging along the ocean floor. We use genome sequencing, transcriptional profiling, and interspecific hybrid analysis to explore the molecular and developmental basis of leg formation.

Evolution of novel sensory organs in fish with legs.

How do animals evolve new traits? Sea robins are fish that possess specialized leg-like appendages used to "walk" along the sea floor. Here, we show that legs are bona fide sense organs that localize buried prey. Legs are covered in sensory papillae that receive dense innervation from touch-sensitive neurons, express non-canonical epithelial taste receptors, and mediate chemical sensitivity that drives predatory digging behavior.

Molecular tuning of sea anemone stinging.

Jellyfish and sea anemones fire single-use, venom-covered barbs to immobilize prey or predators. We previously showed that the anemone uses a specialized voltage-gated calcium (Ca) channel to trigger stinging in response to synergistic prey-derived chemicals and touch (Weir et al., 2020).

Molecular tuning of sea anemone stinging.

Jellyfish and sea anemones fire single-use, venom-covered barbs to immobilize prey or predators. We previously showed that the anemone uses a specialized voltage-gated calcium (Ca) channel to trigger stinging in response to synergistic prey-derived chemicals and touch (Weir et al., 2020).

Investigation of the spermathecal morphology, reproductive strategy and fate of stored spermatozoa in three important thysanopteran species.

In insects, females can keep sperm capable of fertilisation over a long period with the help of the spermatheca. The effectiveness of storing fertile sperm is expected to reflect in the reproductive strategy and, thus, the morphology of the involved organs. In this work, we focused on the relationship between reproduction and morphology in the haplodiploid Thysanoptera, especially if a loss of these traits occurs under thelytoky.

Sperm ultrastructure in arrhenotokous and thelytokous Thysanoptera.

Thysanoptera are haplo-diploid insects that reproduce either via arrhenotoky or thelytoky. Beside genetically based thelytoky, this reproduction mode can also be endosymbiont induced. The recovery of these females from their infection again leads to the development of males.

Honeybee colonies compensate for pesticide-induced effects on royal jelly composition and brood survival with increased brood production.

Sublethal doses of pesticides affect individual honeybees, but colony-level effects are less well understood and it is unclear how the two levels integrate. We studied the effect of the neonicotinoid pesticide clothianidin at field realistic concentrations on small colonies. We found that exposure to clothianidin affected worker jelly production of individual workers and created a strong dose-dependent increase in mortality of individual larvae, but strikingly the population size of capped brood remained stable.

Reproductive Behavior of Echinothrips americanus (Thysanoptera: Thripidae).

Most Thysanoptera possess a haplo-diploid reproductive mode and reproduce via arrhenotoky. Females can mature eggs successively throughout almost their entire life, but in most terebrantian thrips spermiogenesis is complete by adult male eclosion, and testes contain only mature spermatids. In parasitoid wasps this phenomenon of preadult spermiogenesis is described as prospermatogeny.

Male Pheromones Influence the Mating Behavior of Echinothrips americanus.

Two dibasic esters, the dimethyl ester of hexanedioic acid (dimethyl adipate, DBE-6) and the dimethyl ester of pentanedioic acid (dimethyl glutarate, DBE-5) were found in head-thorax extracts of male Echinothrips americanus. DBE-5 induced abdomen wagging and raising in males and females, which is typically exhibited when encountering a male. DBE-6 was avoided by males and was detected on mated, but not on virgin, females.

Sternal gland structures in males of bean flower thrips, Megalurothrips sjostedti, and Poinsettia thrips, Echinothrips americanus, in comparison with those of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae).

Sternal pores are important features for identification of male thrips, especially within the subfamily Thripinae. They vary in shape, size and distribution even between species of one genus. Their functional role is speculated to be that of sex- and/or aggregation pheromone production.

Curable genetic instability of a gal4 transgene in Drosophila.

Transgenes, especially those driving production of the GAL4 transcription factor in a specific spatial pattern, are a critical and widely used tool in the Drosophila research community. We recently noticed loss of GAL4-driven reporter gene expression in a series of crosses, and traced that loss of reporter gene expression to stochastic physical loss of the GAL4 gene in the driver line. We have demonstrated that the instability of the GAL4 transgene can be "cured" by treatment of the line with tetracycline, suggesting that the causative agent is of bacterial origin.