Male reproductive investment relative to age and flight behaviour in the monandrous butterfly Pararge aegeria

Male reproductive investment may signify a considerable cost to male insects that produce sperm packages or spermatophores. Male butterflies allocate much of their active time budget to mate location, and they may adopt different behavioural strategies to do so. In the speckled wood butterfly (Pararge aegeria L.), males adopt either a territorial wait-and-fight strategy (territorial perching) or a fly-and-search strategy in wider areas (patrolling). In this study, we analysed the impact of male age, male size and male behaviour (i.e. behavioural strategies and levels of activity) on spermatophore investment (i.e. spermatophore mass, number of eupyrene sperm bundles). As predicted, reproductive investment increased with male age and size. Nevertheless, the increase of spermatophore mass with age and the number of eupyrene sperm bundles (i.e. fertile sperm) was stronger in low-activity males compared to active flying males. This suggests that flight activity has a negative impact on male reproductive investment. However, males that were forced to fly in the laboratory produced more eupyrene sperm bundles than resting males. We discuss the potential effects of male–male competition and predation risk on current versus future male reproduction. Males adopting different mate-locating strategies (perching and patrolling) in outdoor cages did not differ in spermatophore traits as was predicted from their very different flight performances. Copulations of territorial perching males took somewhat longer than copulations with non-perching males. There was a significant family effect of spermatophore size and of the expression of male mate-locating strategies suggesting heritable variation. Female traits (i.e. age and size) did not strongly affect spermatophore production. We discuss the results relative to both ultimate and proximate explanations of the complex relationships between butterfly activity, behavioural strategies, age and spermatophore production.     

Whole-body 3D kinematics of bird take-off: key role of the legs to propel the trunk

Previous studies showed that birds primarily use their hindlimbs to propel themselves into the air in order to take-off. Yet, it remains unclear how the different parts of their musculoskeletal system move to produce the necessary acceleration. To quantify the relative motions of the bones during the terrestrial phase of take-off, we used biplanar fluoroscopy in two species of birds, diamond dove (Geopelia cuneata) and zebra finch (Taeniopygia guttata). We obtained a detailed 3D kinematics analysis of the head, the trunk and the three long bones of the left leg. We found that the entire body assisted the production of the needed forces to take-off, during two distinct but complementary phases. The first one, a relatively slow preparatory phase, started with a movement of the head and an alignment of the different groups of bones with the future take-off direction. It was associated with a pitch down of the trunk and a flexion of the ankle, of the hip and, to a lesser extent, of the knee. This crouching movement could contribute to the loading of the leg muscles and store elastic energy that could be released in the propulsive phase of take-off, during the extension of the leg joints. Combined with the fact that the head, together with the trunk, produced a forward momentum, the entire body assisted the production of the needed forces to take-off. The second phase was faster with mostly horizontal forward and vertical upward translation motions, synchronous to an extension of the entire lower articulated musculoskeletal system. It led to the propulsion of the bird in the air with a fundamental role of the hip and ankle joints to move the trunk upward and forward. Take-off kinematics were similar in both studied species, with a more pronounced crouching movement in diamond dove, which can be related to a large body mass compared to zebra finch.     

Temporal variations in the level of chlordecone in seawater and marine organisms in Martinique Island (Lesser Antilles)

Environmental Science and Pollution Research - The present study, conducted in the Galion Bay in Martinique, aims to highlight the temporal and seasonal variations of chlordecone contamination (an...     

Gaudeamus lavocati sp. nov. (Rodentia, Hystricognathi) from the early Oligocene of Zallah, Libya: first African caviomorph?

A new African species of hystricognathous rodent, Gaudeamus lavocati sp. nov., is described herein from the early Oligocene deposits of Zallah locality (Sirt basin, Central Libya). The dental morphology of this species is very close to that of some earliest South American caviomorphs. It allows a reinterpretation of molar crest homologies among earliest caviomorphs, pentalophodonty being confirmed as the plesiomorphic molar condition in Caviomorpha. This morphological resemblance argues for close affinities between Gaudeamus and earliest South American hystricognaths. Cladistic analysis supports Gaudeamus lavocati sp. nov. as the first known African representative of Caviomorpha, implying that its ancestors were part of the African phiomyid group that crossed the South Atlantic by a direct immigration route. Alternatively, the series of derived dental features of Gaudeamus could also be interpreted as evolutionary synchronous convergences of an African hystricognath lineage towards the specialized pattern of some caviomorphs. However, the high level of similarities concerning teeth morphology and enamel microstructure and the similar age of fossiliferous strata on both continents make this interpretation less probable. The phylogenetic position of this taxon is of considerable importance because it represents an enigmatic component of the phiomorph–caviomorph radiation in Africa and appears as a new clue toward the understanding of caviomorph origins.     

The Need for Flexibility in Conservation Practices: Exotic Species as an Example

To garner support for biodiversity from the World’s human population, conservation biologists need an open-minded, integrated conservation strategy. We suggest that this strategy should include efforts to (1) preserve existing high quality, diverse ecosystems, (2) remediate impaired systems, (3) balance the needs of people and ecological resources, and (4) engender appreciation of nature and its services. We refer to these four key tenets as reservation, restoration, reconciliation, and reconnection. We illustrate these concepts by presenting the debate surrounding the management of exotic species from an unusual perspective, the benefits of exotic species. By this example we hope to encourage an integrated approach to conservation in which management strategies can be flexible, adjusting to society’s needs and the overall goals of conservation.     

Comparing the effect of elevated pCO2 and temperature on the fertilization and early development of two species of oysters

This study compared the synergistic effects of elevated pCO₂ and temperature on the early life history stages of two ecologically and economically important oysters: the Sydney rock oyster, Saccostrea glomerata and the Pacific oyster, Crassostrea gigas. Gametes, embryos, larvae and spat were exposed to four pCO₂ (375, 600, 750, 1,000 μatm) and four temperature (18, 22, 26, 30°C) levels. At elevated pCO₂ and suboptimal temperatures, there was a reduction in the fertilization success of gametes, a reduction in the development of embryos and size of larvae and spat and an increase in abnormal morphology of larvae. These effects varied between species and fertilization treatments with S. glomerata having greater sensitivity than C. gigas. In the absence of adaptation, C. gigas may become the more dominant species along the south-eastern coast of Australia, recruiting into estuaries currently dominated by the native S. glomerata.