It is a very difficult task to see lobsters mating in the wild because they have very private habits and remain hidden under rocks. When they do come out it is at night, because they are nocturnal, so it is difficult to watch their behavior in their natural environment without affecting their actions in any way. Despite the setbacks, scientists do know a few things about the mating systems of lobsters in general. The knowledge that they have was acquired from laboratory observations in artificial habitats.
When the time is approaching for the females to shed their shells, they initiate this pairing by repeatedly going to where the male lobster lives. The pair lives together for a couple days and when the females are about to molt they jab the male they are living with. The male Panulirus cygnus approach the soft females, and turn them over onto their backs. The males proceed to put their ventral surface to the females in a head-to-head fashion. Spermatophores emerge from the male's genital opening and the male rock lobsters transfer a packet of sperm to the females, and stick this jelly-like fluid matrix of sperm between her last pair of legs. It appears as a tar spot. The freshly placed sperm go into the oviduct of the females, and as the fluid matrix disappears, the sperm are released to fertilize the female's eggs. This whole mating process takes about 30-60 seconds.
In a day or two the female lobsters move to a different shelter to finish hardening their shells. No sooner do the females leave the males' shelter, does another female move in to go through the same process she just completed. This goes on until all the females in that male's area have their eggs fertilized. For females, mating is serial monogamy because only one exclusive pair is formed during each breeding season. However, for males, mating is serial polygyny because they form exclusive bonds with a series of females during each breeding season.
Mating System: monogamous ; polygynous
The breeding season for adults is during the late winter. They generally spawn for the first time between the ages of 6 and 7. The females have a final pre-spawning molt and then wait for optimum weather and food conditions. It is possible that the lunar cycle or rising water temperature produce the biological urge for courtship.
The eggs are laid between September and January and depending on the size of the female, 300,000-700,000 eggs are produced. Over a number of weeks the eggs develop inside the mother until the cephalothorax is filled with a bright orange, caviar mass.
Once hatched, the rock lobster larvae, phyllosoma, go to the surface with the other planktonic animals. They move by the current of the ocean, or by attaching to a jellyfish. Understandably, morality rates are very high during this 9-11 month time period.
Breeding season: Late Winter
Average number of offspring: 300,000-700,000 eggs laid.
Average gestation period: 95 days.
Average time to independence: few minutes.
Average age at sexual or reproductive maturity (female): 6-7 years.
Average age at sexual or reproductive maturity (male): 6-7 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
The eggs are eventually laid, after 3-4 hours of work, through holes at the base of the third pairs of legs. When the eggs are laid, they are attached to the setae (fine hairs) on the abdominal swimmerets of the females. The females carry the eggs while they develop for a maximum of 95 days, and then they hatch. Females carrying eggs are called, berried, because the appearance of the developing eggs is similar to that of berries. Once the eggs are hatched, the mothers leave the babies to fend for themselves.
Parental Investment: no parental involvement; female parental care
- Bliss, D. 1982. Shrimps, Lobsters, and Crabs. New Century Publishers, Inc.
- Griffin, D. 2001. "High Morality of Western Australian Rock Lobster Larvae During El Nino" (On-line). Accessed December 04, 2004 at http://iri.columbia.edu/climate/ENSO/societal/example/Griffin.html.
- Imgrund, J. 1999/2000. "Western Rock Lobster: Panulirus cygnus" (On-line ). Accessed 03/12/03 at http://aqwa.com.au/lobster.html.
- Monchaux, A. n/a. "Do Crayfish Dream?" (On-line). Accessed December 04, 2004 at http://users.wiredcity.com.au/~ademonchaux/stories/crayfish.html.
- Phillips, B. 2002. "Department of Fisheries- Recreational Fishing- Fishing for Rock Lobsters" (On-line). Life Cycle of the Western Rock Lobster. Accessed December 04, 2004 at http://www.fish.wa.gov.au/rec/broc/rocklob/rllife.html.
- Taylor, J. 2002. "Biology of Lobsters" (On-line). Marine Crustaceans of Southern Australia. Accessed December 04, 2004 at http://www.museum.vic.gov.au/crust/page1a.html.
- The Lobster Conservancy, 1998. "Lobster Biology: Adults" (On-line). Accessed December 05, 2004 at http://www.lobsters.org/tlcbio/biology10.html.
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