The potential of parasitoid Hymenoptera as bioindicators of arthropod diversity in agricultural grasslands

Abstract

Summary 1.As measuring biodiversity in its entirety is impractical, there is a need for bioindicators. This study tested the hypothesis that parasitoid Hymenoptera are potential bioindicators that provide a useful means to assess the wider biodiversity of arthropod populations in agro-ecosystems. There are a range of theoretical arguments to support such a claim, including the high trophic position of these taxa within the arthropod communities in which they occur, and the unique nature of their biological relationships with the majority of terrestrial arthropod groups. 2. A survey of 48 commercial farms was conducted and Generalized Linear Models used to investigate relationships between six taxa-parasitoid Hymenoptera, Coleoptera, Hemiptera, Diptera, Araneae and plants (species richness and sward height)-in agricultural grasslands. As well as relationships between these groups, the relationship of each individual group to the overall biodiversity of all other arthropod groups was explored. 3. Both abundance (r 2 = 0AE58) and taxon richness (r 2 = 0AE54) of parasitoid Hymenoptera had stronger relationships with overall arthropod taxon richness than any other arthropod group investigated. Parasitoid abundance also had a positive relationship with species richness of Coleoptera (r 2 = 0AE23) and Hemiptera (r 2 = 0AE47).4. An historical data set demonstrated how the relationship between parasitoid abundance and overall arthropod taxon richness changes over the growing season. July, when the relationship was strongest, is potentially the most useful time to sample. 5. For use in routine monitoring, it is important that an effort be made to understand the seasonal influence on the relationship in the context being studied. Equal sampling effort must be made for all sites being compared and sites should be sampled as close together in the season as is possible. 6. Synthesis and applications. We show that, within agricultural grasslands, both the abundance and taxon richness of parasitoid Hymenoptera are more closely related with overall arthropod diversity than any other arthropod group investigated. The use of parasitoid abundance provides a simple and practicable monitoring tool for tracking change in wider arthropod diversity in agroecosystems.

Can Host Plant Richness be Used as a Surrogate for Galling Insect Diversity?

“…Bräuniger et al [28] also showed that plant species richness might be a good surrogate for predicting galling insect diversity. Usually, when one factor is correlated with the presence of certain taxa, this factor can be considered a surrogate for the diversity of this taxon [24,29,30].…”

The use of the biodiverse parasitoid Hymenoptera (Insecta) to assess arthropod diversity associated with topsoil stockpiled for future rehabilitation purposes on Barrow Island, Western Australia

“…As per the procedural steps in developing bioindicators (McGeoch 1998, MeGeoch 2007, further investigation and testing is required to more robustly establish the relationship between the abundance and species richness composition of the parasitoid wasp assemblage (or components thereof) and the diversity of other potential host taxa in the context of the monitoring program. The parasitoid Hymenoptera were demonstrated to be efficient tools for monitoring of the variations in diversity of arthropod assemblages in agricultural grasslands in Ireland (Anderson et al 2011). In addition to the potential of parasitoid Hymenoptera to be bioindicators of biodiversity, there exists the potential for them to be effective ecological indicators.…”

“…It has only been in relatively recent times that the potential use of parasitoid wasps as indicators of arthropod diversity and community structure has begun to be developed and evaluated. Studies have shown that the abundance and diversity of parasitoid wasp species can provide a more reliable indication of overall arthropod diversity than any other group (Anderson et al 2011, Jensen 1997, Stephens 2005. Further to this, the composition of parasitoid taxa and respective functional groups present have the potential to provide insights into the responses of the soil, grassland and litter associated invertebrates to various agro-ecosytem management practices, impacts of weed invasion into native ecosystems, and reforestation initiatives (Anderson et al 2011, Jensen 1997, Maeto et al 2009, Stephens 2005.…”

Optimising Capture Methods for the Evaluation of Parasitoid Wasp Diversity

“…There is growing evidence demonstrating the potential of Hymenoptera as indicator taxa for environmental assessments, or as surrogates for extrapolating the diversity of other taxa (Mazón, 2015;Anderson et al, 2011;Rohr et al, 2007).…”