Apportionment of nuptial alkaloidal gifts by a multiply-mated female moth (Utetheisa ornatrix): eggs individually receive alkaloid from more than one male source

Summary. In the moth Utetheisa ornatrix the female is promiscuous and receives a nuptial gift of pyrrolizidine alkaloid (PA) by seminal infusion from each mate. The alkaloidal gifts are transmitted by the female to the eggs, which are protected as a result. We here show that individual eggs may receive PAs from more than one male source and that individual males have no assurance that the PA they themselves contribute to the female will find its way exclusively to eggs of their siring. Received 28 June 2002; accepted 28 August 2002.     

Prenatal diagnosis of a double bisatellited marker with an unusual copy number ratio

Prenatal diagnosis, by amniocentesis, revealed mosaicism with respect to a bisatellited, apparently dicentric, DA/DAPI positive, de novo marker. The following cell lines were observed in decreasing order of frequency: 46,XX > 48.XX, + mar, + mar » 47,XX, + mar. The pregnancy was terminated and post-mortem examination revealed an apparently normal fetus. Cytogenetic studies of fetal and placental tissues revealed approximately the same level of mosaicism together with the unusual copy number ratio seen in the amniotic fluid cultures. Non-disjunction at the first post-zygotic mitotic division giving rise to a mosaic: 46,XX/ 48,XX, + mar, + mar followed by subsequent mitotic instability of the marker could account for the unusual copy number ratio.     

Corematal function in Utetheisa ornatrix: interpretation in the light of data from field-collected males

Summary. Males of the moth Utetheisa ornatrix produce a pheromone, hydroxydanaidal, contained in two brush-like organs, the coremata, which they evert during courtship. Hydroxydanaidal is derived chemically by the males from pyrrolizidine alkaloids that they sequester from their larval food plants. It had been shown previously that the amount of hydroxydanaidal in the coremata correlates positively with a number of male parameters that are a measure of the male’s “worth.” Hydroxydanaidal could thus be used by the female as a basis for discrimination in courtship. Experiments carried out with virgin Utetheisa had shown that females do indeed mate selectively with males of high corematal hydroxydanaidal content, thereby accruing the multiple benefits that are the consequence of such selectivity. Unresolved was the question whether corematal hydroxydanaidal could still provide a basis for female appraisal of suitors when these had previously mated. Given the proven promiscuity of the female, male Utetheisa could be expected to be promiscuous as well. Evidence we present here shows that field-collected males, which could be expected to be mostly non-virginal, are of reduced acceptability to females. They are also, on average, in possession of lower quantities of hydroxydanaidal, explaining possibly why they should be held in lesser regard. At low levels, however, hydroxydanaidal does not lend itself for precise assessment of male worth, because as we show herein, at such levels, the compound does not correlate with any of the criteria of male quality (male size, spermatophore mass, male pyrrolizidine alkaloid content, amount of pyrrolizidine alkaloid transmitted to the female). Males that have mated beforehand are therefore likely not to be classed into subcategories by the females, but simply as belonging to one category of “less desirables”. The significance of these findings to our understanding of the mating strategy of Utetheisa is discussed.     

Using land as a control variable in density-dependent bioeconomic models

The bioeconomic analysis of endangered species without consumptive values can be problematic when analysed with density-dependent models that assume a fixed environment size. Most bioeconomic models use harvest as a control variable, yet when modelling non-harvestable species, frequently the only variable under control of conservationists is the quantity of habitat to be made available. The authors explore the implications of this in a model developed to analyse the potential population recovery of New Zealand’s yellow-eyed penguin. The penguin faces severe competition with man for the terrestrial resources required for breeding and has declined in population to perilously low levels. The model was developed to estimate the land use required for recovery and preservation of the species and to compare the results to current tourism-driven conservation efforts. It is demonstrated that land may serve as a useful control variable in bioeconomic models and that such a model may be useful for determining whether sufficient incentives exist to preserve a species. However, the model may generate less useful results for providing a specific estimate of the optimal allocation of land to such a species.     

Single-species versus multiple-species models: the economic implications

Ecologists frequently note the importance of modelling entire ecosystems rather than individual species, but most bioeconomic models in the current literature focus on a single species. While the mathematical difficulty of modelling multiple species may be substantial, it is important to recognise the implications of the single-species assumption to a model’s results. In this paper, the authors address the economic significance of this assumption through the development of an analytical multiple-species model and demonstrate the importance of ecological interrelationships and economic values to the survival of endangered species.     

Landesweite immissionsbezogene Flechtenkartierung in Bayern

In 1996 within a country-wide research project, the epiphytic lichen vegetation throughout Bavaria was mapped according to Guideline VDI 3799, Part I (1995). The data providing information about air quality was collected in 190 sites. Most of the sites demonstrated little to moderate pollution, while both very high and very low levels of air pollution could be found locally. The methods outlined in Guideline VDI 3799 were slightly modified and adapted to the situation in Bavaria. Comparison of the lichen vegetation on different species of trees showed that a rigid classification of tree species as proposed in the guideline is not necessary in Bavaria. The use of several species of trees per site has proven to be favourable. The influence of the natural heterogeneity of the air-quality index in the investigated area was examined. Here, the geology turned out not to be a crucial factor. With respect to climate, it is especially the alpine region with its high levels of precipitation that stands out against the other parts of Bavaria. The results from that area may not be freely compared to those from the remaining sites. It could be shown that the Guideline VDI 3799 is applicable for large-area lichen mapping in Bavaria.