Pygidial Glands in Carabidae, an Overview of Morphology and Chemical Secretion

Predator community structure is an important selective element shaping the evolution of prey defence traits and strategies. Carabid beetles are one of the most diverse families of Coleoptera, and their success in terrestrial ecosystems is related to considerable morphological, physiological, and behavioural adaptations that provide protection against predators. Their most common form of defence is the chemical secretion from paired abdominal pygidial glands that produce a heterogeneous set of carboxylic acids, quinones, hydrocarbons, phenols, aldehydes, and esters. This review attempts to update and summarise what is known about the pygidial glands, with particular reference to the morphology of the glands and the biological function of the secretions.

Endocrinology

The medical term ‘hormone’ was only introduced in 1905 to describe the chemical secretion from an endocrine gland. Since then, there has been tremendous progress in the field of endocrinology, as a result of advances in biochemistry, physiology, genetics, and molecular biology. Recently, advances in molecular biology, particularly sequencing of the human genome, have led to the unravelling of hormone receptor-post-receptor mechanisms. These discoveries have uncovered novel therapeutic targets for endocrine disease. This chapter covers recent clinical trials, in order to show the impact of some of the most crucial evidence in endocrinology in the late twentieth and twenty-first century.

Recognition of Mates in the Portuguese Millipede, Ommatoiulus-Moreletii

The mating behaviour of the Portuguese millipede, Ommatoiulus moreletii, was observed in the laboratory. Male attention towards females appeared to be initiated on contact. Mating activity was more frequent in the night phase of the photoperiod and was not inhibited by darkness. This suggested that a visual signal was not important in mate recognition. Females without antennae mated readily, but males without antennae did not, which suggests that males use their antennae to recognise females. Experiments in T-mazes and petri dishes showed that males were not attracted towards females, nor did they increase activity in the presence of females they could not touch, which implied that an airborne signal such as a volatile pheromone was not used. It was concluded that males use some characteristic of the female cuticle, possibly a chemical secretion, to recognise mates.

The Chemistry of Ants. IV. Terpenoid Constituents of Some Dolichoderus and Iridomyrmex Species

Terpenoid constituents have been isolated from the following Dolichoderus and Iridomyrmex ants. Dolichodial, a novel dicarbonyl compound (C10H14O2), has been extracted from D, acanthoclinea clarki (Wheeler), and D. acanthoclinea dentata (Forel). It has also been obtained from I. myrmecodiae (Emery). The known compounds, methylheptenone and iridodial, have been isolated from I. nitidiceps (Andre). D. diceratoclinea scabridus (Roger) yields (i) methylheptenone and iridodial, or (ii) isoiridomyrmecin, or (iii) dolichodial, dependent on the ant colony. Such variations in the nature of the chemical secretion of different colonies of ants, which are taxonomically indistinguishable, have not previously been reported. Similarly, I. rufoniger (Lowne) yields (i) methylheptenone and iridodial, or (ii) dolichodial.

The natural mechanism for evoking the chemical secretion of the stomach (preliminary communication)

The enquiry was directed to answering the following questions:― 1. What is the comparative value of different food substances in evoking the chemical secretion of the stomach? 2. What channels of absorption are available for the different food substances? Experiments in a previous communication to the Society indicated that the mucous membrane of the pyloric end of the stomach contained the gastric hormone, and was therefore probably a channel of absorption. No direct proof was at that time able to be adduced.