Evidence for hilltopping in bumblebees?

1. Male bumblebees are known to exhibit a range of mate‐location behaviours, including perching on prominent objects and darting at passing queens, patrolling of scent‐marked flight routes, and waiting outside nest entrances for virgin queens to emerge. Here we provide evidence for a fourth strategy, known as hilltopping. This behaviour is widely known from a range of invertebrates, but has not previously been described in bumblebees. 2. We studied the distribution of bumblebees along transects ascending four hills in Scotland and demonstrate that, relative to workers, males of four bumblebee species or species groups (Bombus lapidarius, B. monticola, B. pascuorum, and B. lucorum/magnus/cryptarum/terrestris) tend to congregate at or near the tops of hills. This is, to our knowledge, the first evidence for hilltopping in bumblebees and the first record of any putative mate‐locating behaviour for male B. pascuorum, a very common species in Europe. 3. We note that, in common with most previous studies of mate‐locating behaviour in bumblebees, attraction of virgin queens and mating were not observed.     

Indication of an Anal Pore in Gnathostomulida

Two species of Haplognathia (Gnathostomulida, Filospermoidea) were examined by electron microscopy and found to possess a tissue connection between the posterior end of the intestine and the dorsal epidermis. This anal tissue connection is characterized by a thinned out epidermis, interdigitation of epidermal and intestinal cells, and the absence of the basement membrane. An open anal pore was not observed. It is possible that the anal tissue connection of Haplognathia serves as a functional anal pore. The implications of this discovery with respect to the various theories of early Metazoan evolution are discussed.     

A note on the accessory glands of the reproductive system of the scolopendromorph centipede, Cormocephalus anceps anceps Porat

The function of the reproductive accessory glands has not before been investigated. Their prominence arouses interest in their possible function. A preliminary histological, histochemical, and biochemical analysis has been undertaken in order to start to answer this question. No definite conclusions can, however, be made from the results obtained. From evidence accumulated on the behaviour of the sexes and the peaks of secretion production it seems likely that the product of the female glands would be used to coat the eggs with a colleterial substance. The male Geophilomorpha, Scolopendromorpha, and Lithobiomorpha all spin webs on which they place a spermatophore during courtship, and all three groups possess two well developed pairs of accessory glands which may be responsible for the production of web material. The Scutigeromorpha, on the other hand, only possess a single vestigeal pair of glands and do not spin a web. It is suggested that the accessory glands of the male produce web material although this still remains unproven.     

Long-term natal site-fidelity by immature lemon sharks (Negaprion brevirostris) at a subtropical island

Although many sharks begin their life confined in nursery habitats, it is unknown how rapidly they disperse away from their natal area once they leave the nursery. We examine this issue in immature lemon sharks ( Negaprion brevirostris ) from the time they leave the nursery (∼ age 3) at a subtropical island (Bimini, Bahamas), through to the onset of sexual maturity (∼ age 12). From 1995 to 2007 we tagged and genotyped a large fraction of the nursery-bound sharks at this location (0–3 years of age, N  = 1776 individuals). From 2003 to 2007 we sampled immature sharks aged from 3 to 11 years ( N  = 150) living around the island and used physical/genetic tag recaptures coupled with kinship analysis to determine whether or not each of these 'large immature sharks' was locally born. We show that many island-born lemon sharks remain close to their natal area for long periods (years) after leaving the nursery; more than half of the sampled sharks up to 135 cm total length (∼6 years old) were locally born. The fraction of locally born sharks gradually declined with increasing shark size, indicating that dispersal is relatively slow and does not primarily occur after sharks reach a threshold size. Local conservation measures (e.g. localized fishery closures, marine protected areas) can therefore help protect island-born lemon sharks even after they leave the nursery habitat.     

NITROGEN EXCRETION IN THE ANTARCTIC LIMPET NACELLA CONCINNA (STREBEL, 1908)

Excretion of ammonia, urea and primary amines (assayed as fluorescamine-positivesubstances, FPS) was measured in the Antarctic limpet Nacellaconcinna. The mean contributions to overall excretion rate were89% ammonia, 8% urea and 3% FPS, although in some individualsurea formed almost 40% total excreted nitrogen and in othersprimary amines formed over 30%. Ammonia and urea excretion rateswere not correlated, suggesting the ureagenesis has a specificphysiological role and is not simply an alternative end-pointto ammonia. In starved limpets urea excretion at first increasedby at least x2, and then declined to low levels after 44 days.Ammonia excretion also increased, but only after 20 days, andthen stayed high until at least day 44. These different patternsconfirm the independent roles of ammonia and urea productionin Nacella. (Received 10 June 1993; accepted 25 August 1993)     

Glycinebetaine Biosynthesis and Accumulation in Unstressed and Salt-Stressed Wheat

McDonnell, E. and Wyn Jones, R. G. 1988. Glycinebetaine biosynthesisand accumulation in unstressed and salt-stressed wheat.—J.exp. Bot. 39: 421–430. A preliminary study was made of the pathway of glycinebetainebiosynthesis in wheat and compared with that of spinach. Thedata obtained provided further evidence that there is a fundamentaldifference in the biosynthetic pathway between the Gramineaeand the Chenopodiaceae. A detailed study was then made of the pattern of glycinebetaineaccumulation during development of unstressed and salt-stressedwheat. The content of glycinebetaine in the leaves of unstressedplants increased as each leaf developed and decreased rapidlythereafter. In salt-stressed leaves an initial increase in glycinebetainecontent was observed which also coincided with leaf expansion.The glycinebetaine content of the stressed leaves then beganto decrease only to increase again. The roots and grain of bothstressed and unstressed plants had high glycinebetaine contentsat the onset of germination but these declined rapidly as theplants grew. A possible link between glycinebetaine biosynthesisand membrane lipid biosynthesis in wheat is discussed. Key words: Glycinebetaine, salt stress, membrane lipid, wheat