Evol Ecol Res 13: 461-477 (2011) Full PDF if your library subscribes.
Dietary differences among colour morphs of pygmy grasshoppers revealed by behavioural experiments and stable isotopes
Einat Karpestam and Anders Forsman
School of Natural Sciences, Linnaeus University, Kalmar, Sweden
Correspondence: A. Forsman, School of Natural Sciences, Linnaeus University, 391 82 Kalmar, Sweden.
Question: Do alternative colour morphs differ in food preferences and realized dietary niches?
Hypothesis: Colour morphs represent alternative phenotypes that exploit different dietary niches due to combined effects of differences in food preferences and physiological demands, availability and spatial distribution of alternative food types, and morph-specific microhabitat utilization.
Organisms: Adult female Tetrix subulata pygmy grasshoppers belonging to one of three colour morphs: dark, pale or striped. Colour pattern in these grasshoppers is genetically influenced and barely, if at all, affected by developmental plasticity in response to environmental cues. Tetrix subulata inhabits damp places, primarily on the soil surface, and feeds on algae, short grass, moss, and humus. We collected and studied individuals of seven populations in southeast Sweden: three from pastures, two from alkaline fens, and two from burnt clear cuts.
Methods: First, we performed two multiple-choice feeding experiments: (1) between individuals from five different source populations, and (2) between individuals of different colour morphs from the same population. Second, we measured natural abundances of carbon and nitrogen stable isotope ratios (δ13C and δ15N) in free-ranging individuals from two populations to test for differences in long-term diets among populations and colour morphs.
Results: In the multiple-choice feeding experiments, utilization of food types differed both among populations and among colour morphs within a population. The comparisons of stable isotope ratios indicated long-term differences in diet both among populations and among colour morphs.
Conclusions: Food preferences and dietary niches differ among pygmy grasshopper populations and colour morphs.
Keywords: colour polymorphism, insect, niche, resource partitioning, Tetrix subulata.
DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.
© 2011 Anders Forsman. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.
Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.
All copies of abstracts and articles must preserve their copyright notice without modification.