Morpho-functional comparison of the Dufour gland in the female castes of the Amazon ant Polyergus rufescens (Hymenoptera, Formicidae)

Abstract

The Dufour gland is crucially involved in main aspects of the parasite habit of the slave-making ant Polyergus rufescens, i.e. slave-raids and host colony usurpation. Workers use chemicals from this gland as recruitment signals during raid organization, while newly-mated queens use its secretion to appease residents during host nest invasion. Here, we report a comparison of the general morphology and fine structure of the Dufour gland in the female castes of P. rufescens: queens, ergatogynes (intermediate forms), and workers. The analysis clearly shows the link between gland structure and its behavioural role in queens and workers. In particular, queens present a hypertrophied gland with an extended lumen and a thin epithelium no more active in secretory function. This is consistent with the fact that usurper queens use the Dufour gland contents only during the short phase of host nest penetration. Contrary to adult queens, the cytoplasmic organization of the Dufour gland epithelium of raiders is typical for a tissue with secretory activity (abundance of mitochondria, free ribosomes, strands of smooth endoplasmic reticulum and a Golgi apparatus). This is consistent with the continuous raiding activity performed by workers throughout their adult life. The biology of ergatogynes is still an enigmatic matter. Their Dufour gland is intermediate in shape and size between that of queens and workers. It presents a fairly thick epithelium with features that are typical of a quite active secretory tissue.

Chemical communication in mating behaviour of the slave-making ant Polyergus rufescens (Hymenoptera, Formicidae): 3-ethyl-4-methylpentanol as a critical component of the queen sex pheromone

“…Populations of this species are widespread along the northern and central part of the Italian peninsula. Although the main features of its parasitic lifestyle are the raiding behaviour and the dependent colony founding through usurpation , several other aspects of its morphology, biology, ecology, and behaviour can be related to its nature as a social parasite (Hçlldobler and Wilson, 1990;Le Moli et al, 1994;Grasso et al, 1997Grasso et al, , 2005Billen et al, 2001). For instance, its mating behaviour is an example of "Female-calling Syndrome" (Hçlldobler and Bartz, 1985), a strategy in which females typically call for males, do not disperse widely, and remain near a conspecific colony after mating .…”

Morphology and Ultrastructure of the Female Reproductive Apparatus of an Asexual Strain of the Endoparasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera, Braconidae)

“…The ultrastructure of the Dufour gland was well studied in many Hymenoptera, including ants, bees, and several families of parasitic wasps [17,65,66]. The ultrastructure of the epithelial cells in M. pulchricornis is similar to those mentioned above, but the structures are simpler.…”

General morphology and ultrastructure of the female reproductive apparatus of Trichomalopsis shirakii crawford (Hymenoptera, Pteromalidae)

“…The layer of microvilli surrounding the lumen represents an enlargement of cell surface and may facilitate the secretory product into gland lumen. The ultrastructure of Dufour gland have been well studied in many Aculeates, including ants, bees and wasps and several families of parasitic Hymenoptera (Abdalla, ; Abdalla, ; Billen, ; Blass and Ruthmann, ; Gnatzy et al, ; Grasso et al, ). The ultrastructure of the epithelial cells in T. shirakii is similar to those mentioned above, but the microvilli are more apparent.…”