Journal of Insect Conservation

Alinvi, Ola; Ball, J.; Danell, K.; Hjältén, J.; Pettersson, R.

doi: 10.1007/s10841-006-9012-2pmid: N/A

The use of saproxylic beetle community as a metric to evaluate nature conservation measures in forests requires efficient methods. We first compare traditional bark sieving to a potential improvement (extracting beetles from whole bark with Tullgren funnels) to determine the most efficient. Secondly we compare this most efficient bark sampling to eclector and window traps. At the species, family, and functional group levels, we consider species richness, abundance and practical aspects. Traditional bark sieving missed >50% of the individual beetles compared to whole bark sampling so we recommend the latter. Window traps caught large numbers of mobile saproxylic beetles, but a high proportion of non-saproxylics results in high sorting cost; bark sampling and eclector traps had a high proportion of saproxylics and obligate saproxylics. Compared to bark sampling, eclector traps are non-destructive, and monitor the whole saproxylic assemblage (i.e. also beetles inside the wood). Overall, window traps are useful because they capture saproxylic beetles attracted to dead wood and sample the local species pool, whereas eclector traps capture the saproxylics that actually emerge from a particular piece of dead wood, and thus are suited to detailed studies. Overall, we suggest that a combination of these two best methods is highly complementary.

Cassel-Lundhagen, Anna; Sjögren-Gulve, Per

doi: 10.1007/s10841-006-9023-zpmid: N/A

Dispersal between habitat patches may be important for the long-term persistence of populations. We conducted a mark–release–recapture study and analysed the dispersal pattern in the scarce heath butterfly inhabiting a network of suitable habitat patches using stepwise logistic regression (SLR) and the Virtual Migration (VM) model. We also analysed the influence of different types of matrices.

Nagamitsu, Teruyoshi; Kenta, Tanaka; Inari, Naoki; Horita, Haruka; Goka, Koichi; Hiura, Tsutom

doi: 10.1007/s10841-006-9025-xpmid: N/A

To assess the impact of Bombus terrestris invasion on the foraging efficiency of native Japanese bumblebees, consumption and acquisition of floral resources during foraging on flowers of native Japanese plant species were investigated using enclosures with three treatments: one with only B. terrestris (exotic), one with both B. terrestris and native Japanese bumblebee species (mixed), and one with only Japanese species (native), but with the bumblebee density held constant. Changes in the body mass of queens and the nest mass of colonies for two days did not significantly differ among four combinations of the species and treatment, B. terrestris in the exotic and mixed treatments and Japanese species in the mixed and native treatments. Thus, it is not clear that B. terrestris has higher foraging efficiency than native species and that B. terrestris individuals more negatively affect the foraging efficiency of native species than individuals of the native species themselves. The nectar standing crop of Cirsium kamtschaticum was smaller in the exotic treatment than in the mixed and native treatments. However, this may have been an artifact of differences in the numbers of flowers in the various treatments.

Hannon, Eugene; Hafernik, John

doi: 10.1007/s10841-006-9027-8pmid: N/A

Habitat degradation led to local extinction of the San Francisco forktail damselfly (Ischnura gemina) in Glen Canyon Park, San Francisco, California. In this study, we reintroduced I. gemina into Glen Canyon after the damselfly’s habitat was restored. Upon release, we carried out a mark- release-recapture study to monitor the damselfly’s population dynamics. Our data were compared to two “baseline” studies on I. gemina, conducted in the park prior to the damselfly’s demise. Our recapture rates were significantly lower than the prior studies due to a large initial decline in marked individuals upon release. Despite a lower recapture rate, the reintroduction was initially successful since the damselflies reproduced throughout the summer and the following year. However, the population failed to persist during the second year when the habitat became degraded with excess vegetation. Future success is contingent on the continual management and upkeep of the habitat.

Salama, Nabeil; Knowler, John; Adams, Colin

doi: 10.1007/s10841-006-9029-6pmid: N/A

Macro-moths caught in a Rothamsted trap, operating from 1968 to 2003 as part of the Rothamsted Insect Survey, were used to investigate the long-term population trends of moth populations on East Loch Lomondside. In total 367 species of macro moth were recorded during this study. Over the 35 years of this study, an increase was recorded in both the overall number of individuals and moth diversity. Mean annual temperature significantly predicted the change in moth diversity but not number of individuals caught. Four of the most consistently abundant species, collectively constituting 27% of the average annual catch, were subjected to more detailed analysis. The three species that emerge during the summer months Eulithis populata (the northern spinach), Hydriomena furcata (july highflier) and Idaea biselata (the small fan-footed wave) became more abundant throughout the study period, (although for the latter species not significantly so). For Eulithis populata and Idaea biselata their emergence time became earlier, over the study period and in Eulithis populata and Hydriomena furcata, the flight duration also became longer. In contrast, the species that emerges as an adult during autumn and winter, Epirrita dilutata (the november moth) did not exhibit a significant change in abundance, emergence date or flight duration in this study. The results suggest that climate change is at least in part, responsible for the observed changes in species dynamics.

Dennis, R. L. H.; Hardy, P. B.

doi: 10.1007/s10841-006-9032-ypmid: N/A

In conserving organisms, a bipolar view has generally been adopted of landscapes, in which resources are allocated to patches of habitats and the matrix ignored. Allocating additional resources to the matrix would depend on two conditions: first, that organisms search for resources in landscapes regardless of differences in vegetation types and resource availability; second, that when resources occur in the matrix they are used by species. Behavioural data linked to biotope and substrate types, on three pierid species (Pieris brassicae, P. rapae, P. napi), have been examined to explore the relationship between flight modes and resource availability. Search flight and resource use, taken as measures of resource quests, occur extensively in all biotopes and over all substrates in addition to direct linear flight, more typical of butterflies when migrating between habitat units. Resource seeking and using even exceed direct flight in some biotopes that have been regarded generally as lacking in resources for these butterflies. For example, such is the case for P. brassicae in woodland and for P. rapae in scrub. This finding supports the view for repairing the matrix and enhancing the general countryside outside habitat patches with resources increasingly being made for organisms. The proviso is that species’ requirements are adequately researched and resourced so as not to become sinks.

Gibb, Heloise; Hjältén, Joakim

doi: 10.1007/s10841-006-9033-xpmid: N/A

Fire is important in maintaining a diversity of communities and landscapes in boreal ecosystems, but, in recent times, forest management has suppressed fires. Managers now commonly burn a proportion of clear-cuts in Sweden to conserve components of the fire-favoured fauna, but effects of these treatments on the ant fauna are unknown. We compared ant communities between burned and control clear-cuts to determine their value for this important faunal group. Ants were collected in 1995 and 1996 from 5 burned and 5 control clear-cuts in mid-boreal Sweden. We compared abundances of workers and reproductive females of common species between the treatments. Burned and control clear-cuts supported similar abundances of common species, differing only in the abundance of Leptothorax acervorum queens collected in 1995. This suggests that L. acervorum was attracted to the burning, but we did not detect an increase in the abundance of its workers the following year. The abundance of dominant red wood ants (F. rufa group) was not correlated with that of any other species, suggesting that their patchy occurrence did not conceal differences between treatments. Our findings suggest that nests of many ant species survive low severity fires. Habitat structure is likely to be important in determining ant community structure and low severity burning in disturbed open habitats, such as the clear-cuts examined in this study, may not significantly alter habitat structure relative to unburned habitats in the short term.

Nakamura, Akihiro; Catterall, Carla; House, Alan; Kitching, Roger; Burwell, Chris

doi: 10.1007/s10841-006-9034-9pmid: N/A

The present study investigated the impacts of rainforest clearance, and associated subsequent land␣use for pasture, on assemblages of soil and litter arthropods in eastern subtropical Australia. We assessed the utility of soil and litter arthropods as potential bio-indicators of cleared and forested habitats. Arthropods were sampled from 24 sites (12 sites each in rainforest and pasture) using two methods (extraction from litter, pitfall traps). Responses of taxa were analysed at various levels of taxonomic resolution, including ‘coarse’ arthropods (all arthropods sorted to Order/Class), ant genera and ant species. Multivariate analyses of arthropod composition indicated that an increase in the level of taxonomic resolution did not provide a commensurate increase in the sensitivity of assemblage response. Indicator values (IndVals), computed for each taxon, showed that a number of arthropod taxa may have potential as bio-indicators of habitat change. However the use of many of these, especially many ant species found in our study, may be unreliable because even after extensive numbers of sites were sampled, most species showed patchy distributions. To overcome this problem, we generated ‘composite indices’, by combining information from sets of indicator taxa. The utility of these composite indices is discussed.

Rouquette, James; Thompson, David

doi: 10.1007/s10841-006-9030-0pmid: N/A

A successful conservation strategy for an insect species should address the habitat requirements of all life stages and all activities performed by those life stages. In this paper the night-time roosting habitat and behaviour of the endangered damselfly Coenagrion mercuriale (Odonata: Coenagrionidae) was investigated by marking damselflies with UV fluorescent paint. Night-time observations revealed that individuals did not roost together and those that were recorded on more than one occasion did not return to the same spot each night. There was no apparent preference for roosting close to the watercourses. C. mercuriale roosted towards the top of the vegetation and this vegetation was considerably taller than the mean height of the vegetation in the study area. Adults were strongly associated with two tussock-forming monocots, Juncus inflexus and Deschampsia cespitosa. Differences in the abundance of these plants were shown to result in large differences in the numbers of C. mercuriale roosting in different parts of the site. The importance of providing these structural elements of habitat as part of a wider conservation strategy for this species is discussed.

Watts, Phillip; Thompson, David; Allen, Katherine; Kemp, Stephen

doi: 10.1007/s10841-006-9024-ypmid: N/A

DNA obtained from museum specimens provides a historical perspective on levels of genetic diversity. Archived samples are irreplaceable so it is desirable that only parts of the specimens are used, which constrains the amount of DNA obtained from small taxa. However, at present there are no quantitative data on yields of DNA from such samples. In this paper we determine the amount of DNA that may be extracted from the legs of museum-archived specimens of the damselfly Coenagrion mercuriale (Charpentier) and the suitability of this DNA for PCR-amplification of nuclear genetic loci (microsatellites). We find that (i) the yield of DNA correlates with the genotyping success rate and (ii) the amount of DNA obtained from the legs decreases with time since sample collection until 1954, before which no DNA could be detected (although DNA may be present in very low quantities). This cut-off point for successful DNA extraction corresponds with the date until reliable genotypes could be obtained by routine PCR. Thus, air-dried insect legs more than 50 years old appear to have limited usefulness for studies that seek to amplify many nuclear loci without the use of other techniques that may be used to increase the possible low-quantities of template DNA present.