What determines whether a species of insect is described? Evidence from a study of tropical forest beetles

Abstract

1. The rainforest canopy has been called 'the last biological frontier', and if this is true, there should be more undescribed species in this stratum than the ground stratum.2. Here, we test this and other hypotheses regarding traits of described and undescribed species by a sub-sample of 156 species into 96 described and 60 undescribed species from a beetle assemblage of 1473 species collected from the canopy and ground in an Australian lowland rainforest.3. We show that described species are significantly more likely to be in the canopy, are more likely to be larger and, if they are large, are more likely to have been described earlier.4. Undescribed species are just as likely to be found near the ground as in the canopy and are more likely to be smaller. 5. After the first year of sampling, 'new' described and undescribed species not previously encountered continued to appear in each of three further years of trapping.6. These data show that the canopy fauna is in fact relatively 'well known', and that the undescribed species to be found in both strata are likely to be smaller than described species and are less likely to be plant feeders. ResultsOf the 156 species examined, 96 (61.5%) were assessed to be described species and 60 (38.5%) to be undescribed (Table 1).116 Nigel E. Stork et al.

A decade of change in the saproxylic beetle fauna of eucalypt logs in the Warra long-term log-decay experiment, Tasmania. 1. Description of the fauna and seasonality patterns

“…There are few available datasets to put the Warra proportion in an Australian context. In a study of tropical rainforest beetles in NE Queensland (Stork et al 2008), just under two-fifths of the beetle species collected were undescribed-a proportion that the authors considered would rise had their study included all beetle families rather than a selection of the more tractable ones. Both these figures probably reflect the predominance in the sampled faunas of small, non-phytophagous species which historically have been given less taxonomic attention than large, phytophagous species (Kitching 2006); they may also reflect both the diversity of Australian insect faunas generally, and a long-standing paucity of available taxonomic expertise in Australia (Yeates et al 2003).…”

Biases in biodiversity: wide-ranging species are discovered first in the deep sea

“…Analyses of particular taxa or functional groups have shown that wide-ranging or conspicuous species are discovered earlier than small species or those with narrow ranges (Gaston et al, 1995;Allsopp, 2003;Collen et al, 2004;Stork et al, 2008). The extent to which this bias is a phenomenon in the marine realm has so far only been tested for zooplankton and coastal fish species in the tropical eastern Pacific (Gibbons et al, 2005;Zapata and Robertson, 2007).…”

Oak canopy arthropod communities: which factors shape its structure?

“…Historically, studies in forest canopies were limited by access techniques and collection methods (Nadkarni 1994;Sutton 2001). The standardization of new access and collection methods started in the 1970s; from studies of only descriptive interest, researchers started to investigate the distribution, abundance and biodiversity of organisms, structure and functioning of the associated communities, and the dynamics of the ecosystems (Nadkarni and Parker 1994;Mitchell 2001;Stork et al 2008). As access (i.e., balloons, cranes, platforms, bridges) and sampling methods (i.e., sprays, light traps, hand collecting) have evolved, canopy research became a viable option for researchers in many scientific disciplines, such as botany, zoology, landscape and ecosystem ecology, meteorology, conservation biology, etc.…”