The role of niche breadth, resource availability and range position on the life history of butterflies

Abstract

We analysed the relationship between three life history characteristics (mobility, length of flight period and body size) and niche breadth (larval host plant specificity and adult habitat breadth), resource availability (distribution and abundance of host plants) and range position (distance between the northernmost distribution record and southernmost point of Finland) of the butterfly fauna of Finland. The data is based on literature and questionnaires. Often in across species studies phylogeny may create spurious relationships between life-history and ecological variables. We took the phylogenetic relatedness of butterfly species into account by analysing the data with phylogenetically independent contrasts (CAIC method). Butterfly mobility was positively related to the niche breadth, resource availability and range position. The length of the flight period was negatively related to the range position, indicating that the species at the northern edge of their distribution range have shorter flight period than species which are further way from the range edge. After controlling for the phylogenetic relatedness we found no significant correlations between body size and niche breadth, resource availability or range position. We suggest that the relationship between the length of the flight period and range position may arise as a consequence of lower hatching asynchrony in edge species as a result of lower environmental variance in larval growth conditions. Our results on the mobility suggest that there is selection pressure towards lower migration rate in species that have restricted niche breadth, low resource availability and in species that are on the northern edge of their geographical distribution range. In such species, selection against mobile individuals is likely to result from the decreased probability of finding another habitat patch suitable for egg laying

Adult longevity and its relationship with conservation status in European butterflies

“…Furthermore, a high level of temporal fragmentation, namely short individual life span in relation to long light period, in combination with protandry seriously reduced the efective population size (sensu Lande and Barrowclough 1987;Hill 1972), thus accelerating the loss of genetic variability in small populations. In contrast to several earlier studies, which suggested that extinction risk in butterlies decreases with lengthening light period (Komonen et al 2004;Kotiaho et al 2005;Franzen and;Johannesson 2007), our analyses did not reveal any link between light period length alone and species conservation status. The most straightforward explanation for such a result could be that light period length per se is unimportant for species extinction risk, and it only matters in combination with adult longevity.…”

Predicting the risk of extinction from shared ecological characteristics

“…We used female wing span (mm) as a measure of butterfly body size, because there is a very strong positive correlation between female and male body size (22). Wing-span measurements for both sexes are based on Marttila et al (19), in which the mean of a sample of 20 individuals was given, with an exception of some rare species with fewer individuals measured.…”

“…Finally, we construct an ecological extinction risk rank to predict which species face the highest risk of becoming extinct. Our data are predominantly based on published literature (18)(19)(20)(21)(22).…”

Geographical variation in wolf spider dispersal behaviour is related to landscape structure

“…Greenwood et al 1978;Ims 1990;Sorci et al 1994;Negro et al 1997;Massot & Clobert 2000) and winged invertebrates (e.g. Den Boer 1970;Roff 1997;Komonen et al 2004). Unlike winged arthropods, spiders (Araneae) and mites (Acaridae) often perform aerial dispersal in a predominantly uncontrolled mode (e.g.…”