Thyroid status in juvenile alligators (Alligator mississippiensis) from contaminated and reference sites on Lake Okeechobee, Florida, USA

Exposure to environmental contaminants has been shown to alter normal thyroid function in various wildlife species, including the American alligator (Alligator mississippiensis). Abnormalities in circulating levels of the thyroid hormone thyroxine (T₄) have been reported in juvenile alligators from several contaminated lakes in Florida. To further elucidate these functional thyroid abnormalities, this study examines the structure of thyroids and circulating T₄ concentrations from juvenile alligators collected from three sites of varying contamination on Lake Okeechobee, Florida. The following variables were used to characterize thyroid morphology: epithelial cell height, width and area, percent colloid, and follicle area. These variables were compared among study sites and between genders. No difference was detected in epithelial cell height, epithelial cell area, or follicle area among the sites, whereas significant differences in epithelial cell width (p=0.02) and percent colloid (p=0.008) were found. Animals from the most contaminated site (Belle Glade) had significantly greater epithelial cell widths and significantly less colloid present in their follicles compared to animals from the reference site (West). Gender did not have a significant interaction with site for any variable measured. Thyroxine (T₄) concentrations were elevated in the intermediately contaminated site (Conservation Area 3A) compared to the other sites (p<0.0001). It is proposed that the disruptions seen in Lake Okeechobee alligators are due to disruptions at both the thyroid and extra-thyroidal tissues.     

Wasps robbing food from ants: a frequent behavior?

Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes. (1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more common than previously thought.     

Communal nesting, kinship, and maternal success in a social primate

Communal nesting, where several mothers regularly pool and cooperatively rear offspring, is unusual in mammals. This type of crèching behavior is especially rare among primates, with the notable exceptions of humans, some nocturnal strepsirrhines, and—as we show in this study—black-and-white ruffed lemurs (Varecia variegata). Here, we combine data on nesting behavior, genetic relatedness, and infant survivorship to describe variation in ruffed lemur infant care and to examine the potential benefits of ruffed lemur communal breeding. Reproductive events were rare, and females produced litters (synchronously) only once in 6 years of observation. We show that not all mothers participate in communal crèches, but those that did had greater maternal success; communal breeders spent more time feeding and their offspring were more likely to survive. Although cooperating mothers were often related, females also cooperated with non-kin, and those who shared infant care responsibilities had greater maternal success than mothers who did not participate. If there is indeed a causal link between maternal cooperation and reproductive success, this unusual behavior, like that of human communal rearing, may have evolved via some combination of kin selection and mutualism.     

Bird disturbance on conservation sites in Brittany (France): the standpoint of geographers

Bird disturbance by human activities is one of the impacts related to human presence at conservation sites in Brittany (France). This paper is an attempt at reviewing this relatively unknown problem through the results of an international bibliographical review and of a regional inquiry conducted in close collaboration with managers of the conservation areas in Brittany. These two approaches will help to demonstrate the extent and complexity of the human / fauna interactions, as well as to take stock of the state of research in this field and, last but not least, to highlight the difficulties managers of conservation sites are facing to deal with this new issue. For the managers, bird disturbance is indeed the most important impact related to human attendance on conservation sites in Brittany.     

使用底栖和浮游桡足类生物测试评估沉积物修复方案的效果

三丁基锡（TBT）是一种常见于船舶防污涂料中的有机锡化合物。尽管该化学物已于2008年被禁用,但在ports和港口等海上交通区域仍可检出致毒水平（浓度）的TBT。一项补救方案在新西兰的一个港口实施,以将TBT和铜的浓度降低到可接受的（浓度）值。这项研究使用分析化学和桡足类生物测试相结合的方法评估了该方案的有效性。在港口内的三个空间梯度上采集沉积物和水样,并在修复前后测定了有机锡和金属含量。利用底栖和浮游桡足类生物测试估算了沉积物和淘析样品的毒性。虽然底泥样品的急性毒性在修复后减少,但对底栖桡足类的繁殖率仍有影响。本研究所采用的方法有望评估沿海地区修复过程的效果。     

The Effects of Photochemical Oxidants on Materials

The excessive cracking of rubber products was one of the earliest indicators of the presence of atmospheric photochemical oxidants. It has been demonstrated that this excessive cracking of rubber is caused by atmospheric ozone formed in the photochemical smog formation process. Depending on the formulation of the rubber, cracking under stress can readily be detected within 3/4 hr when atmospheric oxidant levels are as low as 0.03 ppm. Natural and certain synthetic rubbers are particularly vulnerable. These rubbers when stressed show cracking when exposed to 0.02 ppm laboratory ozone for about 1 hr. Other materials known to deteriorate under atmospheric photochemical smog conditions are textiles and certain dyed fabrics, particularly under conditions of high humidity. Loss of tensile strength of cotton textiles when wet or moist, and similar fading of these dyed fabrics, particularly under high humidity, can be also produced by laboratory exposure of these textiles to pure ozone. Ozone effects on asphaltic materials ate also reported.     

Histopathological lesions and DNA adducts in the liver of European flounder (Platichthys flesus) collected in the Seine estuary versus two reference estuarine systems on the French Atlantic coast

An epidemiological survey was conducted in the Seine estuary and in two smaller and relatively preserved estuaries on the French Atlantic coast in order to estimate the occurrence of liver lesions in European flounder, Platichthys flesus, and also to seek putative risk factors for the recorded pathologies. Four hundred and seventy-eight fish of both sexes and of different size ranges were sampled in the three studied areas, 338 of which in the Seine estuary. All fish were examined for histopathological liver lesions, while DNA adducts and otoliths were analyzed on a subsample. Five categories of hepatic lesions were recorded with the following prevalence for the Seine estuary: 36.7 % inflammations, 8 % parasites (mainly encysted nematodes), 6.5 % foci of cellular alteration (FCA), 5.3 % foci of necrosis or regeneration (FNR), and 1.5 % tumors. Inflammation occurrence increased according to age, contrary to parasitic infestations and FCA which were more prevalent in young fish, notably those of <1 year old (group 0). Tumors were only observed in females of more than two winters. Females exhibited a higher prevalence of tumors (3.0 %) and FCA (6.5 %) than males (0 and 2.6 %, respectively). Parasitic and infectious lesions and FNR were equally distributed in males and females. The prevalence of FNR was also shown to vary according to sampling season, with significantly more occurrences of liver necrosis in the fish collected in summer than in spring. Spatial differences were observed with a higher occurrence of encysted parasites in flounders from the upper Seine estuary, while inflammations predominated in flounders living downstream. Temporal trends were also noted, with an increased prevalence of parasitic infestations, inflammations, and FCA in the 2002–2003 period in comparison to the 1996–1997 one. The three flounder populations from the Seine estuary (Normandy), Ster estuary (Brittany), and Bay of Veys (Normandy) showed different spectra of hepatic lesions. Flounders from the Bay of Veys had relatively few liver lesions as compared to flounders from the two other estuaries. Flounders from the Ster estuary exhibited the highest prevalence of parasites (37.2 %) and inflammations (51.1 %). Finally, FCA and liver tumors occurred at very similar levels in both flounder populations from the Seine and the Ster estuaries. Group 0 flounders inhabiting the upper Seine estuary were more prone to parasitic and pre-neoplastic hepatic lesions and had higher levels of liver DNA adducts than the older ones living downstream. It was postulated that group 0 European flounders may serve as valuable bioindicators for assessing the quality of estuarine waters and the health status of euryhaline fish populations.