Sampling of parasitoid Hymenoptera: influence of the height on the ground

Ricardo Chan-Canché,Horacio Ballina-Gómez,Jorge Leirana-Alcocer,Santiago Bordera,Alejandra González-Moreno

doi:10.3897/jhr.78.54309

Ricardo Chan-Canché, Horacio Ballina-Gómez + Show 3 more

Open Access

https://doi.org/10.3897/jhr.78.54309

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Abstract

Parasitoid hymenopterans are a highly diverse group of insects; therefore, the choice of an adequate sampling method becomes important to achieve a representative species richness of a site. The aim of this work is to evaluate the size and diversity of parasitoids in relation to the height of the Malaise trap placement above the ground of a low deciduous forest from Yucatan, Mexico. Parasitoids were collected from September to October 2015, using three Malaise traps at ground level and other three located right above the others, leaving no space between them, at a height of 1.5 m. The collected specimens were identified at family level. A total of 4083 parasitoids belonging to 31 families were collected, representing 93% of the sample’s completeness, according to Jack 1 estimator; with differences in richness and abundance between trap heights according to rarefaction and fixed effects multifactorial ANOVA, respectively. Bethylidae, Braconidae and Ichneumonidae were the most abundant families. Besides, when analyzing the differences of each family by separate, there were significant results for Bethylidae, Diapriidae and Ichneumonidae with more individuals in the traps at ground level than in the raised ones. In a further analysis, the effect of body size on the capture height was observed. The specimens of larger size belonging to the families Bethylidae, Sphecidae, Sclerogibbidae and Evaniidae were more collected at ground level, on the other hand, the larger sized Ichneumonidae were collected at raised level.

Highlights

The choice of an adequate sampling method is indispensable to ensure representativeness of the obtained samples and to infer accurate conclusions regarding the diversity of a site
A total of six Malaise traps were placed at two different heights: three of them were placed in the conventional way, at ground level (GMT: Ground Malaise trap) and the others were placed immediately above the first ones, leaving no space between them, at a height of 1.5 m above ground level (RMT: Raised Malaise Trap) (Fig. 1)
A total of 4083 specimens belonging to 31 families of parasitoid hymenopterans were collected, being Bethylidae, Braconidae and Ichneumonidae the most abundant families, representing altogether 40% of the whole sample (Table 1)

Summary

Introduction

The choice of an adequate sampling method is indispensable to ensure representativeness of the obtained samples and to infer accurate conclusions regarding the diversity of a site. Parasitoids represent one of the most important biological strategies due to their role as population control of other insects, mostly phytophagous These insects develop and feed during their larval stage on or inside other insects, which die at the end of the process (Godfray 1994). The Malaise trap is a passive capture system, which works by intercepting insects in flight, becoming especially adequate for capturing hymenopterans, which present positive phototropism; they fly upwards in search of light when in contact with the trap For this reason, it is important that the collecting pot be placed towards the maximum illumination; the trap’s shape leads the insect towards the collecting jar with alcohol (van Achterberg 2009)

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