Species Richness Of Wasps Research Articles

Habitat structure components are effective predictors of trap-nesting Hymenoptera diversity

Habitat heterogeneity can be the major factor affecting species diversity in a community and measuring bee and wasp community habitat preferences in natural systems may provide insights for biodiversity management and conservation. In the present study, we investigate the effects of habitat structure components on solitary bee and wasp species richness and abundance. The research was conducted in an urban forest remnant in southeast Brazil. Our main questions were: (1) is similarity in habitat structure mirrored by similarity in Aculeate assemblage composition? and (2) what are the vegetation features that could be used as predictors of solitary bee and wasp richness and abundance? Aculeate bees and wasps were sampled using trap nests from February to November 2004. Trap nests were placed in sampling units located in 6 ha of secondary mesophytic forest. One hundred and thirty-seven trap nests were occupied by four species of wasps and seven species of bees. Altogether, our sampling units had a mean capture rate (relative to expected richness) of 72% during all the study period. The more similar sampling units were in terms of vegetation structure, the more similar they were in solitary bee and wasp species composition. The variance of tree abundance, shrub height and the abundance of wood logs were good predictors of solitary bee and wasp species richness and abundance in the study area. We demonstrate that even in a small scale it is possible to detect significant influences of habitat features on alpha diversity and that some of them are effective as predictors of trap-nesting Hymenoptera richness and abundance. Die Heterogenität des Habitats kann der Hauptfaktor sein, der die Artendiversität in einer Lebensgemeinschaft beeinflusst. Die Erfassung der Habitatpräferenzen in Bienen- und Wespenlebensgemeinschaften in natürlichen Systemen kann deshalb Einsichten für Biodiversitätsmanagement und -erhaltung ergeben. In der vorliegenden Studie untersuchten wir die Auswirkungen von Komponenten der Habitatstruktur auf den Artenreichtum und die Abundanz von solitären Bienen und Wespen. Die Untersuchung wurde in einem urbanen Waldrest im südöstlichen Brasilien durchgeführt. Unsere Hauptfragen waren: (1) wird die Ähnlichkeit von Habitatstrukturen durch die Ähnlichkeit in der Zusammensetzung der Aculeata-Ansammlungen widergespiegelt? Und (2) worin bestehen die Vegetationsmerkmale, die als Indikatoren für die Diversität und Abundanz von solitären Bienen und Wespen genutzt werden können. Die aculeaten Bienen und Wespen wurden durch Nisthilfen von Februar bis November 2004 beprobt. Die Nisthilfen wurden in den Beprobungseinheiten in einem sechs Hektar großen, sekundären Mesophytenwald platziert. Einhundertsiebenunddreißig Nisthilfen wurden von vier Wespenarten und sieben Bienenarten besetzt. Insgesamt hatten unsere Beprobungseinheiten im Laufe der gesamten Fangperiode eine mittlere Fangrate von 72% (in Bezug auf den erwarteten Artenreichtum). Je ähnlicher sich die Beprobungeinheiten in Bezug auf die Vegetationsstruktur waren, desto ähnlicher war die Zusammensetzung der Bienen und Wespen. Die Varianz der Baumabundanz, der Buschhöhe und die Abundanz von Holzstämmen waren gute Indikatoren für den Artenreichtum und die Abundanz solitärer Bienen und Wespen in der Untersuchungsfläche. Wir demonstrieren, dass es möglich ist, selbst auf einer kleinen Skala signifikante Auswirkungen der Habitateigenschaften auf die Alpha-Diversität festzustellen, und dass einige von ihnen effektive Indikatoren für den Reichtum und die Diverstität der Hymenoptera in Nisthilfen sind.

Response of aculeate Hymenoptera to spatial features of an agricultural landscape

The impact of increasing distance to the edge of neighbouring land-use types on aculeate Hymenoptera was studied in the marginal region of the Lahn-Dill-Bergland (Central Hesse, Germany). Aculeate hymenoptera were sampled two weeks in August using coloured pan-traps that were located along four transects: A. abandoned land with increasing distance to grassland, B. arable land with increasing distance to grassland, C. grassland with increasing distance to abandoned land, and D. arable land with increasing distance to abandoned land. Each transect was completed by adding centres of adjacent sites with the respective interacting land-use type, i.e. centres of grassland to transects A and B as well as centres of abandoned land to transects C and D. The composition of aculeate Hymenoptera did not change along transects A and B, while several parameters of the community structure significantly changed along transects C and D. The species richness of wasps as well as the abundances of hypergaeic aculeate species and prey-specialised wasps was high on abandoned land and abruptly decreased in arable land without further change along the transect. Species richness of total Aculeata and wild bees as well as the abundance of total Aculeata, polylectic bees and endogaeic Aculeata gradually declined on grassland with increasing distance to abandoned land. Oligolectic bees did not respond to distance in any of the treatments investigated. It is concluded that the close association of both arable land and grassland to abandoned land covered with shrubs is a structural feature of cultural landscapes that positively affects the diversity and density of aculeate Hymenoptera. Conservation of areas covered by shrubs is thus an important management option.

African Fig Wasp Communities: Undersaturation and Latitudinal Gradients in Species Richness

We examined species richness patterns for the wasps associated with southern and central African figs (Ficus) to determine if fig wasp communities are saturated with species and if the degree of saturation (or undersaturation) differs in temperate and tropical communities. Saturation was tested by regressing local wasp-community richness (alpha diversity) against the regional wasp species richness (gamma diversity) of each fig species, and latitudinal variation in saturation was tested by regressing local community species richness against latitude