| Summary: | Crayfish chelae have important functions, including prey capture and manipulation,
reproduction, defense against predators, and inter- and intraspecific
interactions. Consequently a loss of chelae often occurs. Adult
specimens of invasive spiny-cheek crayfish (Orconectes limosus) were
reared from February to November 2008 to observe the ability to regenerate
lost chelae. Percent molt increments (PMI) of postorbital carapace
length (POCL), chela length (ChL) and width (ChW) were compared between
crayfish with and without chelae. Regenerated chelae were found
to grow faster (ChL, ChW) than initial chelae and POCL. This trend occurs
in both reproductive and non-reproductive O. limosus males and females.
Values of 55.6 ± 0.06% for ChL and 50.0 ± 0.06% for ChW, compared
to the initial chelae, were obtained in regenerated chelae of adult
O. limosus after one molt. After two molts regenerated chelae reached
67.6 ± 0.07% ChL and 69.7 ± 0.08% ChW of values for initial chelae.
Growth rate of regenerated chelae decreased with an increase in chelae
dimensions. Regenerated chelae were found to be more narrow (significantly
lower ChW/ChL ratio) than initial chelae. Regenerating of chelae
did not have any influence on POCL growth. This study presents evidence
that the invasive O. limosus possesses the ability of rapid substitution of
lost chelae.
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