Photoperiod and Reproduction in Lobsters (Homarus)

• Published in: American Zoologist
• Main Author: NELSON, KEITH
• Format: Text
• Language: English
• Published: Oxford University Press 1986
• Subjects: Articles; Ice Sheet; Prince Edward Island
• Online Access: http://az.oxfordjournals.org/cgi/content/short/26/2/447; https://doi.org/10.1093/icb/26.2.447

SYNOPSIS. Photoperiodic control of lobster ( Homarus ) oviposition ranges from none in the European species ( H. gammarus ) to a two-phase requirement in some populations of H. americanus . In the inshore population from Massachusetts two to three months of shortday photoperiod appear necessary to condition the ovary for final vitellogenesis following long-day onset (LDO). The stimulus of LDO is only effective near the time of molt. If molt follows LDO within 120 days, egg extrusion follows the molt in about 80 days. If LDO follows the molt, extrusion occurs in about 125 days. Extrusion delayed in this way delays the following molt, which is also delayed by the retention of eggs on the pleopods. In lobsters from Prince Edward Island the photoperiodic response seen at laboratory temperatures ( ca . 14°C) appears to be subordinated to a response to other cues, probably temperature, when females are held on a near-natural temperature regime with winter minimum of 2°C characteristic of inshore environments. H. americanus from the migratory outer continental shelf population experience winter temperatures rarely lower than 8°C and probably require photoperiodic control to initiate migration as well as vitellogenesis. The photoperiodic response may have originated in offshore populations during the Pleistocene and spread to more northerly inshore areas as habitat opened after the retreat of the continental ice sheet.