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1. Giant sperm in a Neotropical moth Xenosoma geometrina (Lepidoptera: Arctiidae)

Creator:
Morrow, Edward H.
Type:
article, model:article, and TEXT
Subject:
Lepidoptera, Arctiidae, Xenosoma, eupyrene, apyrene, sperm size, sperm competition, and Costa Rica
Language:
English
Description:
The stereotypical sperm is characterised as being tiny but produced in great quantities. However a few species (frequently insects) produce much larger spermatozoa, probably with an associated cost in reduced numbers per ejaculate. Here I present the first evidence that a species within the Lepidoptera also produces giant sperm. It seems likely that given wider sampling this record for the largest sperm produced by a lepidopteran may subsequently be broken.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2. Phenotypic plasticity in sperm traits in scorpionflies (Mecoptera: Panorpidae): Consequences of larval history and seasonality on sperm length and sperm transfer

Creator:
Vermeulen, Andreas, Engels, Sierk, Engqvist, Leif, and Sauer, Klaus Peter
Type:
article, model:article, and TEXT
Subject:
Mecoptera, Panorpidae, ejaculate expenditure, larval rearing density, spermatogenesis, sperm competition, and sperm size
Language:
English
Description:
We examined effects of seasonality, larval food availability and larval rearing density on sperm length, sperm transfer rates and body size in the bivoltine scorpionfly Panorpa vulgaris. Males of the first annual generation were larger and had larger sperm. Comparing individuals of two summer generations showed that adult males resulting from group bred, ad libitum fed larvae were larger but had smaller sperm than males resulting from singly kept, food deprived larvae. Thus, sperm size is not a simple function of body size. Instead, we suggest that sperm size modification was caused by varying rearing densities. Group bred individuals produced smaller sperm but transferred at higher rate. This indicates a trade-off between sperm number and sperm size as predicted by evolutionary models of sperm production. Given the strong influence of larval history in our present work, we recommend that future studies investigating the consequences of varying sperm competition risk or intensity on male gametic strategies should also control for larval history in order to avoid distorting effects.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public