Search results for "dams"

Interspecific territoriality in Calopteryx damselflies: the role of secondary sexual characters

2006

Interspecific territoriality is usually interpreted to result from interspecific interference competition, although it may also originate from mistaken species recognition. In the latter case, it may be based on similarity of secondary sexual characters. In the damselfly Calopteryx splendens, males have pigmented wing spots as a sexual character, and males with the largest spots resemble males of another species, Calopteryx virgo. Probably because of this resemblance, C. virgo males are more aggressive towards large- than small-spotted C. splendens males. We examined whether wing spot size of C. splendens males affects territorial interactions between the species. In a removal experiment, t…

Factors Affecting Interspecific Aggression in a Year-Round Territorial Species, the Jewel Damselfish

2012

Vertebrates live in complex species networks in which interspecific interactions are common. In some contexts, the aggressive behaviours shown in these interspecific interactions are very similar to those shown in intraspecific interactions. It is still an open question whether intra- and interspecific aggression share common causality. We studied a year-round territorial species the jewel damselfish, (Plectroglyphidodon lacrymatus), which cultivate algae they feed on. Territory holders aggressively defend these algae that are an attractive resource for many other species. In this study, we recorded territorial aggression in free-living individuals and recorded aggressive responses to a sta…

Saxonagrion minutus nov. gen. et sp., the oldest damselfly from the Upper Permian of France (Odonatoptera, Panodonata, Saxonagrionidae nov. fam.)

1999

Abstract Saxonagrion minutus nov. gen. et sp. was found in the Saxonian (Salagou Formation) of the Lodeve basin. It is the oldest and the first record of the modern infra-order Panodonata in the Palaezoic (Upper Permian of France). The present discovery supports the hypothesis concerning the persistance of many groups of Odonatoptera through the Permo-Triassic boundary.

Novel host-specific iron acquisition system in the zoonotic pathogenVibrio vulnificus

2015

Summary Vibrio vulnificus is a marine bacterium associated with human and fish (mainly farmed eels) diseases globally known as vibriosis. The ability to infect and overcome eel innate immunity relies on a virulence plasmid (pVvbt2) specific for biotype 2 (Bt2) strains. In the present study, we demonstrated that pVvbt2 encodes a host-specific iron acquisition system that depends on an outer membrane receptor for eel transferrin called Vep20. The inactivation of vep20 did not affect either bacterial growth in human plasma or virulence for mice, while bacterial growth in eel blood/plasma was abolished and virulence for eels was significantly impaired. Furthermore, vep20 is an iron-regulated ge…

Risk of Local Extinction of Odonata Freshwater Habitat Generalists and Specialists

2014

Understanding the risk of a local extinction in a single population relative to the habitat requirements of a species is important in both theoretical and applied ecology. Local extinction risk depends on several factors, such as habitat requirements, range size of species, and habitat quality. We studied the local extinctions among 31 dragonfly and damselfly species from 1930 to 1975 and from 1995 to 2003 in Central Finland. We tested whether habitat specialists had a higher local extinction rate than generalist species. Approximately 30% of the local dragonfly and damselfly populations were extirpated during the 2 study periods. The size of the geographical range of the species was negati…

The influence of thermal extremes on coral reef fish behaviour in the Persian Gulf

2019

AbstractDespite increasing environmental variability within marine ecosystems, little is known about how coral reef fish species will cope with future climate scenarios. The Arabian/Persian Gulf is an extreme environment, providing an opportunity to study fish behaviour on reefs with seasonal temperature ranges which include both values above the mortality threshold of Indo-Pacific reef fish, and values below the optimum temperature for growth. Summer temperatures in the Gulf are comparable to those predicted for the tropical ocean by 2090-2099. Using field observations in winter, spring and summer, and laboratory experiments, we examined the foraging activity, distance from refugia and res…

Regional variations in occupancy frequency distributions patterns between odonate assemblages in Fennoscandia

2018

Odonate (damselfly and dragonfly) species richness and species occupancy frequency distributions (SOFD) were analysed in relation to geographical location in standing waters (lakes and ponds) in Fennoscandia, from southern Sweden to central Finland. In total, 46 dragonfly and damselfly species were recorded from 292 waterbodies. Species richness decreased to the north and increased with waterbody area in central Finland, but not in southern Finland or in Sweden. Species occupancy ranged from 1 up to 209 lakes and ponds. Over 50% of the species occurred in less than 10% of the waterbodies, although this proportion decreased to the north. In the southern lakes and ponds, none of the species o…

Ovia yhteiskuntatieteisiin

2012

Federaliści i rozłam między klasycznością a modernością

2014

The article shows how the classical political thinking, based on civic virtues, and modernist thinking, based on individualism and self-interest, formed the basis of the U.S. Constitution. The Founding Fathers did not realize the full extent of the rift between classicism and modernity. When, as a result of intellectual discussions and practice of social life, this divide began to become more and more obvious, there has been a transition from the classical to the modernist paradigm in American politics. However, the dispute between classicism and modernity still continues and takes on new forms. On the one hand, contemporary political thinking is seen as a triumph of modernism, in which the…

Mazas rakstu ziņas no Ādama

1850

Rokraksts. Latviešu valodā. 19.gs., precīzs gads nav nosakāms