Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

FNZ 47 - Erotylidae (Insecta: Coleoptera: Cucujoidea) - Popular summary

Leschen, RAB 2003. Erotylidae (Insecta: Coleoptera: Cucujoidea): phylogeny and review. Fauna of New Zealand 47, 108 pages.
( ISSN 0111-5383 (print), ; no. 47. ISBN 0-478-09350-0 (print) ). Published 05 Jun 2003

Popular summary

Erotylid beetles

The family Erotylidae (here combined with Languriidae) is composed of approximately 3500 species worldwide, and is another one of those beetle groups that has had few researchers because most species are small, brown, and not considered attractive. But this is true only for the bulk of the species, because many plant-feeding (Languriinae) and fungus-feeding (Erotylini) forms are big, beautiful, and easy to collect and identify. It is only by unfortunate evolutionary reasons that these bigger forms don't occur in New Zealand: New Zealand split off from the ancient continent Gondwana before these bigger groups evolved.

Part of this contribution deals with the development of a classification for the world fauna. Biological classifications allow scientists and the public to communicate about the world of plants and animals by providing a natural reference system that conveys, among other things, where species belong in the tree of life and what taxa they are related to. This taxonomic reference system is typically based on phylogenetic trees that are graphic representations of how life evolved. How the New Zealand members of Erotylidae fit into this new classification is of primary importance for understanding the origins of our local fauna and how they relate to other erotylids.

The New Zealand fauna is rather small, and the 9 species are treated here, while the remaining species in the tribe Erotylini (Thallis and Cryptodacne) are treated elsewhere. The family can be easily separated from other groups, but a microscope will be necessary to discriminate these species from similar families such as Cryptophagidae. The included identification keys will help. The species are not difficult to identify, and some, like Loberus and Cathartocryptus, have distinctive colour patterns that make for easy recognition.

What is extraordinary about the New Zealand species is that these have phylogenetic or family relationships with erotylid beetles throughout the rest of the world. Many species have close relationships with species in Australia, New Caledonia, South America, and possibly South Africa. The unusual genus Loberonotha, found only in New Zealand, may be related to taxa distributed in Boreal Europe, but its exact relationship is unclear and requires additional study.

The family Erotylidae is composed of a mixture of feeding types, and this is reflected in New Zealand's fauna. Cathartocryptus, Cryptodacne, and Thallis are strictly fungus feeding, Loberonotha is plant feeding, perhaps specialising on pollen, and the remaining species are scavengers feeding on plant and fungus tissues. Some species are restricted to certain habitats; for example, Loberus depressus is found commonly at the leaf axes of cabbage trees, and Hapalips can be found in the sheaths of nikau palms. These species can be collected in traps (flight intercept traps) and by sifting leaf-litter. Looking on host plants and fungi provide the best areas for collecting some species.

Like many beetles in New Zealand, most species of Cryptodacne, Loberus, and Thallis are flightless and must walk between food sources. When habitat is destroyed, it may take a long time for these beetles to re-establish themselves in regenerating bush.