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Metabolic adaptations for isopod specialization in three species of D ysdera spiders from the C anary I slands
Author(s) -
Toft Søren,
MacíasHernández Nuria
Publication year - 2017
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/phen.12192
Subject(s) - biology , spider , wolf spider , predation , genus , nutrient , zoology , extraction (chemistry) , ecology , chemistry , chromatography
The spider genus D ysdera is considered to comprise specialist isopod feeders, although the degree of specialization varies between species, depending on morphological (shape of chelicerae), behavioural (attack tactics) and metabolic (food quality of prey) adaptations. D ysdera has radiated extensively in the C anary I slands (currently 47 endemic species are described) and codistributed species have different cheliceral shapes and body sizes indicating different feeding niches. In the present study, we investigate the existence of metabolic adaptations to feeding on isopods by three endemic species ( D ysdera insulana S imon, D ysdera macra S imon and D ysdera verneaui S imon) from T enerife. We hypothesize that there is enhanced extraction efficiency of fundamental macronutrients from isopods compared with control prey in species with special morphological and behavioural adaptations for this prey type. We measure quantitatively spider growth, dry mass consumption, lipid and nitrogen consumption, and calculate growth efficiency and efficiency of utilization of dry mass, lipid and nitrogen. The results show that all three species are able to utilize both prey types, indicating that none of them are strict isopod specialist. D ysdera insulana shows enhanced growth efficiency and D . macra shows enhanced nitrogen extraction efficiency compared with D . verneaui when feeding on P orcellio rather than on M usca . Both traits indicate likely adaptations for the utilization of isopods. Spider species, sex and prey type all affect lipid and nitrogen extraction efficiencies, indicating that spiders do not simply extract nutrients in the proportions available. The results support the hypothesis that adaptations for enhanced digestion of focal prey evolve in species that already have adaptations for enhanced capture success.