The effectiveness and optimal use of Malaise traps for monitoring parasitoid wasps

Abstract

Abstract. 1. Parasitoid wasps are species-rich and likely to be sensitive indicators of environmental change. Malaise traps are widely used for sampling certain taxa of parasitic Hymenoptera, but little is known about how they should best be used to monitor the community at an individual site.2. To investigate the effects of sample duration, trap location and replication on the parasitoid assemblage, we sampled four ichneumonid subfamilies (Hymenoptera: Ichneumonidae) intensively using Malaise traps in two farm woods in the Vale of York, UK.3. Species accumulation curves showed that even with 16 Malaise traps per wood, the community is incompletely sampled. Despite this, we caught up to 28% of all UK species in a single wood, implying that local parasitoid diversity may be very high.4. Abundance and species richness of parasitoids differed significantly between sample periods (fortnights) and between traps, but did not differ overall between core and edge locations.5. Parasitoid community composition differed between core and edge traps, but differences were much stronger in one wood than the other. One subfamily, the Poemeniinae, was found predominantly in edge locations. Catch differences became greater with increasing distance between traps.6. The previous year, two traps in each of the same woods caught only half as many species, but species abundance was positively correlated between years.7. Our results suggest that a small number of traps can contain useful information about the parasitoid community but is likely to seriously underestimate total species richness. To achieve extensive species coverage, sampling should continue over several weeks, with widely separated traps sampling both core and edge locations. Our focal taxa should prove excellent for monitoring the effects of environmental change on biodiversity.

Abelhas (Hymenoptera, Apidae sensu lato) do Estado de Mato Grosso do Sul, Brasil

“…O emprego da armadilha de Malaise contribui com uma informação útil sobre a fauna de abelhas de determinada localidade, mas seu emprego exclusivo possivelmente subestima a riqueza total, como já foi constatado por Fraser et al (2008) para Ichneumonidae (Vespoidea). Na Serra da Bodoquena foi percebido isto pela porcentagem de espécies amostradas pela armadilha de Malaise 17,43% .…”

Optimising Capture Methods for the Evaluation of Parasitoid Wasp Diversity

“…These relative abundances are similar to what were found in the present study. Parasitoid structure is known to be both highly scale and taxondependent (Fraser et al, 2008). However, in order to make valid inferences about parasitoid assemblage structure and rarity, we must assume that the assemblage observed in this study (and others) actually reflect real parasitoid assemblages.…”

“…Catches of parasitoid wasps are frequently characterised by high unevenness and a large proportion of rare species (Fraser et al, 2008;Sääksjärvi et al, 2004). Owen et al (1981) reported 455 species of Ichneumonidae from 6,455 individuals caught over a two year period in a suburban English garden.…”

Description of two techniques to increase efficiency in processing and curating minute arthropods, with special reference to parasitic Hymenoptera

“…Participation in large-scale biodiversity studies and other ecological research projects (Delabie et al 2000;Droege et al 2010;Fisher 2005;LaPolla et al 2007) involving the collection of arthropods with passive collection techniques (Darling and Packer 1988;Fraser et al 2008;Noyes 1989;Townes 1962) generates not only a massive biomass of interest to the conducting researcher, but also a large volume of non-target material, or 'by-catch.' Both of these fractions must be dealt with in an efficacious manner to ensure maximal preservation of the morphological and genomic information of the specimens (Quicke et al 1999).…”