Publication
Title
Male-biased sex ratios in mature damselfly populations: real or artefact?
Author
Abstract
1. There is ongoing controversy about whether biased sex ratios in diploid insect populations are real or an artefact caused by different behaviours and/ or different catchability of the sexes. This was tested by monitoring two field and three semi-natural populations of the damselfly Lestes sponsa. 2. Capture-mark-recapture data showed that population size estimates were about twice as large for males as for females at both field sites. Independent estimates of the sex ratios based on total numbers of males and females captured supported the male bias. 3. Males had higher recapture probabilities than females due to longer times between successive visits in females. Because the same pattern was found in the semi-natural populations, the longer intervals in females are no artefact due to their lower detectability. 4. Theoretical models show that the strong temporary emigration of females tends, if anything, to overestimate female population sizes and that the heterogeneity of recapture probabilities observed in males tends to underestimate male population sizes. Hence, behavioural differences between the sexes do not cause an artificially male-biased sex ratio. 5. Spatial data show that operational sex ratios are male biased at the pond but become female biased in the plots further away from the shoreline; however because of the decrease in densities away from the shoreline, this does not result in a global even sex ratio. 6. Spatial data, temporary emigration patterns, and independent estimates suggest strongly that the male-biased sex ratios in mature damselfly populations are real.
Language
English
Source (journal)
Ecological entomology. - Oxford
Publication
Oxford : 2001
ISSN
0307-6946
Volume/pages
26:2(2001), p. 181-187
ISI
000168256000010
Full text (Publishers DOI)
Full text (publishers version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 29.02.2012
Last edited 23.05.2017
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