Nuptial gift size prolongs copulation duration in the dance fly Empis borealis

Abstract. 1. The time that pairs of the dance fly Empis borealis (L.) (Diptera: Empididae) spent in copula was positively correlated with the volume of the nuptial gift.
2. In some cases the copulation duration was short although prey volume was large. Females engaged in these matings had more worn wings, were therefore older, and most probably had sperm already stored in the spermatheca. It is suggested that these copulations were interrupted because either the spermatheca was full of sperm and the male was not able to transmit any sperm, or because prey content was depleted (males may have fed on the prey or the prey had been used in a previous mating). The latter explanation seemed more probable.
3. A male providing a large nuptial gift may transfer larger quantities of sperm. Quantitative sperm competition is more likely than last-male sperm predominance.     

SOME ASPECTS ON PIGMENT CELL DISTRIBUTION AND FUNCTION IN THE DEVELOPING ECHINOPLUTEUS OF PSAMMECHINUS MILIARIS

Pigment cells in Psammechinus miliaris larvae are frequently found in regions which are morphogenetically active. They can be seen in living larvae from the the midgastrula stage up to metamorphosis. Their early development and typical characters as seen by the electron microscope are described. Histochemical methods have revealed carotenoids which are preferentially located in the pigment granules. The findings are discussed in relation to published data on photopigments. It is suggested that caroteno-proteins of the pigment cells are involved in photo-activated processes which support larval migration and/or morphogenesis.     

Influence of anaerobiosis on the sterol composition of Mucor hiemalis

Strict anaerobic cultures of Mucor hiemalis lead to major modifications of the quantitative and qualitative composition of sterols. Sterols of which the lateral chain contains an ethyl or ethylidene group in C24 are for the first time brought to evidence in a Mucorales. Isolation in the same conditions of E-ethylidene-24 (28) lanostene-8 ol-3 beta lets us suppose that sterols, which are absent in aerobic cultures, are derived from this triterpene of 32 C atoms.