Brief description
Resource owners generally win contests against intruders, a phenomenon referred to as the 'Owner Advantage' (OA). Uca mjoebergi is a typical fiddler crab that is highly sociable, territorial and lives in mixed sex colonies on intertidal mudflats. Burrows are used in territory defence, for mating, and as refuge from predators and environmental stresses. Fights are common between owners and floating males who battle for ownership of the territory and burrow. Experiments were conducted from 28th Sept - 30 Dec 2006 at the lower reaches of Ludmilla Creek within East Point Reserve, 5km North of Darwin, NT. This experiment found that when attacked by naturally occurring floaters, owners were most likely to win fights. Owners won 91.9% of fights against naturally occurring floaters. There is therefore a strong ownership advantage in this species.Lineage
Maintenance and Update Frequency: notPlanned
Statement: 37 fights were documented between naturally occurring floaters and territory owners. The majority of these contests were observed in the field, however 3 fights were assessed using footage from a Sony Digital Video Camera.
Major claw length (manus+pollex) and carapace width of each male were measured to the nearest 0.1mm using dial callipers. Fight duration was either timed in the field using a handheld stopwatch and recorded to the nearest 0.01s, or using a Sony Digital Video Camera after the event.
Statement: 37 fights were documented. A standard set of data was collected for each fight. For each fight the date, time, the type of floater, and winner were recorded. Additionally, all crabs were measured, and fighting phases as well as fight duration were recorded. The winner is the male that owns the territory at the end of a fight. The loser is the crab which walks away at the end of the fight. A fight was considered over when: a) the loser walked >30cm away, b) travelled past two other males territories, c) entered another burrow, or d) started another fight.
Parameters: Datatype (1=field, 2=video), encounter ID, date, ltidet (time of diurnal low tide), hightideht (high tide height of the tide which follows the diurnal low tide), rtimet (time of the fight), tsltide (number of minutes since low tide), ctype (intruder type, NF=Natural Floater), winner, cara (intruder carapace width - mm), chel (inturder cheliped / claw length - mm), ocara (owner carapace width - mm), ochel (owner cheliped / claw length -mm), actions observed (P=push, B=burrow, G=grapple, F=flick, D=dig, Pi=pinch, TB=true burrow fighting), dura (duration of fight - seconds), digdura (dig duration - seconds), sizediff (size difference between owner and intruder claws - mm).
Notes
CreditFunded by The Ecological Society of Australia
Credit
Funded by The Australian Research Council (ARC)
Funded by The Australian Research Council (ARC)
Credit
The Australian National University (ANU)
The Australian National University (ANU)
Purpose
To determine if there was an owner advantage in the fiddler crab Uca mjoebergi.
To determine if there was an owner advantage in the fiddler crab Uca mjoebergi.
Issued: 06 08 2007
Data time period: 2006-09-28 to 2006-12-30
text: westlimit=130.5; southlimit=-13; eastlimit=131; northlimit=-12
text: uplimit=0; downlimit=0
Subjects
28960043 |
ANIMALS/INVERTEBRATES |
ARTHROPODS |
BIOLOGICAL CLASSIFICATION |
BIOSPHERE |
Biosphere | Ecological Dynamics | Competition |
Biosphere | Ecological Dynamics | Dominance |
COMMUNITY DYNAMICS |
Community Structure |
Crustaceans |
EARTH SCIENCE |
ECOLOGICAL DYNAMICS |
Fiddler crabs |
Owner Advantage |
Uca mjoebergi |
biota |
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Other Information
global : 637bba50-417e-11dc-aefb-00188b4c0af8
Identifiers
- global : b74291c0-43bf-11dc-972b-00188b4c0af8
