Males do not prolong copulation in response to competitor males in the polyandrous fly Drosophila bifasciata

Males in many taxa exhibit behavioural plasticity in response to the perceived threat of sperm competition. Drosophila males prolong mating in response to the presence of competitor males before copulation. The benefits of this behaviour to males are evident in Drosophila melanogaster. However, the adaptive nature of the trait is challenged by the observation that it is present in four other Drosophila species, two of which are largely monandrous, raising the possibility that this plasticity is not evolutionarily labile. In the present study, behavioural plasticity and the mating system in Drosophila bifasciata Pominini (Diptera, Drosophilidae) are analyzed. By contrast to other Drosophila species, male D. bifasciata do not exhibit plasticity in copulation duration when competitor males are present before mating. Thus, plasticity in mating duration is not fixed in the genus Drosophila. The mating system of D. bifasciata is also examined. The species is polyandrous but, uncommonly for the genus Drosophila, males transfer a mating plug composed of sperm to females, which forms very shortly after copulation and fills the female uterus. The absence of plasticity observed in D. bifasciata may arise from the sperm plug.     

Miocene barnacle assemblages from southern Spain and their palaeoenvironmental significance

The Tabernas Basin in southeast Spain is a Neogene intermontane basin which filled with sub-aerial and submarine fan conglomerates grading into turbidite sandstones towards the basin centre. The basin history involved the development of Seravallian-Tortonian subaerial fans which coalesced southwards from the basin margin. Increasing water depth in the Tortonian led to a submarine development of these fans. The coarse fan conglomerates are colonized almost solely by barnacles of the species Megabalanus tintinnabulum , known from Miocene-Recent deposits. The barnacles occur in seven preservational-state assemblages, which provide a record of the colonization of stabilized mass-flow conglomerates and of subsequent reworking episodes. M. tintinnabulum is known from intertidal environments today. In situ clusters developed on the fan conglomerates record the transition of the fans from subaerial to submarine environments. Mass-flow deposits rich in barnacle shell debris are representative of basin-wards reworking of intertidal clusters and illustrate relative increase in water depth. A further shallowing episode is identifiable by the recolonization of mass flows by in situ barnacle clusters. This case history is demonstrative of the utility of some barnacles in determining basin history with respect to minor sea level fluctuations.     

REPRODUCTIVE TOURISM AND THE QUEST FOR GLOBAL GENDER JUSTICE

Reproductive tourism is a manifestation of a larger, more inclusive trend toward globalization of capitalist cultural and material economies. This paper discusses the development of cross‐border assisted reproduction within the globalized economy, transnational and local structural processes that influence the trade, social relations intersecting it, and implications for the healthcare systems affected. I focus on prevailing gender structures embedded in the cross‐border trade and their intersection with other social and economic structures that reflect and impact globalization. I apply a social connection model of responsibility for unjust outcomes and consider strategies to counter structural injustices embedded in this industry. The concluding section discusses policy reforms and proposals for collaborative action to preclude further injustices and extend full human rights to all.     

A review of the evidence from in vitro and in vivo studies for a role for phorbol ester tumour promoters from the Euphorbiales in the selection and clonal expansion of specific cell populations

Review of the evidence from in vitro and in vivo studies for a role for phorbol ester tumour promoters from the Euphorbiales in the selection and clonal expansion of specific cell populations. The identification of the active principle of croton oil as 12-0-tetradecanoylphorbol-13-acetate (TPA) and the advent of in vitro studies, facilitated the identification of a plethora of biochemical effects, certain of which could be correlated with biological and differentiation end points. Evidence is presented for the ability of TPA to select and expand specific cell populations in two different cell culture systems. The roles of differentiation state and second messenger systems will be discussed in relation to models of multi-step carcinogenesis.     

Growth and flowering history of Xanthorrhoea johnsonii Lee (Liliaceae) in Toohey Forest Queensland

The settlement of Australia by European man has been a major ecological factor in the history of the vegetation. A reconstruction of one aspect of this influence is given, based on estimations of the growth rate and flowering history of a population of Xanthorrhoea johnsonii .
The age structure of four parts of the existing population within the campus of Griffith University, Brisbane was examined. The mean growth rate, based on counts of leaf production and the number of leaf scars per unit length of the caudexes, was estimated to be 0.88 (s.d. 0.17) cm year^-1. The flowering history was reconstructed from the numbers and positions of flower scars recorded after removal of the leaf bases from 264 individuals. Flowering potential appears to increase up to about 50 years of age and is then relatively stable. Flower production gradually increased from 1820 to 1967 and then fell sharply. Since 1840 there is a strong correlation between the number of residences established within 3 km of the site and the number of flowers produced. The number of plants flowering is known to increase as a result of fire, and we therefore suggest that increasing numbers of accidental or deliberate fires started by settlers and later inhabitants may have caused the increase in flowering.     

Aboveground herbivory affects indirect defences of brassicaceous plants against the root feeder Delia radicum Linnaeus: laboratory and field evidence

1. Belowground herbivory has recently been shown to disrupt the host location behaviour of aboveground parasitoids and thereby impact plants indirect defences. Reverse interactions, on the other hand, have received little attention so far. 2. Lab and field studies were conducted to examine whether the presence of the leaf herbivore Pieris brassicae Linnaeus on brassicaceous plants influences the response of Trybliographa rapae Westwood, a specialist parasitoid of the root feeder Delia radicum Linnaeus. 3. The present results show that the attraction of the parasitoid towards host‐infested plants disappeared when these plants were also infested by P. brassicae. This absence of attraction was observed both when the complete odour blend or only undamaged leaves from damaged plants were offered, emphasising the role of systemically induced volatiles for host location in T. rapae. 4. Furthermore, the field study revealed that parasitism levels dropped from 30% on root‐infested plants to 4% on double‐infested plants. 5. The present study is the first to confirm that reduced attraction to host‐infested plants as a result of simultaneous attack by below‐ and aboveground herbivores translates into lower levels of parasitism in the field.