Reproductive biology and strategies of nine meloid beetles from Central Europe (Coleoptera: Meloidae)

Abstract

The reproductive biology of meloid species from Central Europe is investigated by means of laboratory breeding experiments. They show that the total reproductive potential of meloids, with up to 40,000 eggs, largely exceeds prior data. Furthermore, the number of laid eggs strongly relates to the way by which the triungulins find their host. Clutch size correlates significantly with the size of the beetle, while egg size is independent of this. Both clutch size and egg size decrease with each oviposition. For some species, reproductive data are used to demonstrate how they have adapted to their habitat and to point out existing trade‐offs. Based on the obtained results and on an evaluation of the relevant literature, three types of reproductive strategy can be distinguished within the meloids: (1) very high reproductive rates of open field species with phoretic larvae; (2) average reproductive rates of forest populations of species with phoretic larvae and of species the larvae of which search the nests of their hosts actively; and (3) small to average reproductive rates of those species depositing their clutches in the immediate proximity of their hosts' nests.

Keywords:

• Coleoptera
• host finding
• life history
• Meloidae
• reproductive strategies
• trade‐off
• triungulins

Acknowledgements

We wish to thank Dr Wolfgang Beier (Potsdam), Matthias Forst (Bonn), Klaus Graser (Magdeburg), Dr Frank Lange (Seeheim‐Jugenheim), Prof. Dr Günter Preuß (Landau), Johann Probst (Vienna/Austria), Gerd Reder (Flörsheim), and Sigmund Scharf (Bocholt) for their valuable hints regarding the sites of the Meloidae and for collecting or helping to collect the beetles. Christine Lückmann (Bensheim) supported us in the laboratory work, Dr Thomas Schmidt (Rheinfelden) gave advice on data analysis. In addition to C. Lückmann and Dr T. Schmidt, Prof. Dr Marco A. Bologna (Rome) and Prof. Dr John D. Pinto (Riverside, USA) reviewed the manuscript and gave valuable comments. Special thanks belong to Dr Robert Baumgartner (Münster) for his great support in reviewing and translating the English.