Data

Owner Advantage in the fiddler crab, Uca mjoebergi. Do owners win more contests than floaters because they have a mechanical advantage?

Australian Ocean Data Network
Fayed, Sarah ; Backwell, Patricia, Dr
Viewed: [[ro.stat.viewed]] Cited: [[ro.stat.cited]] Accessed: [[ro.stat.accessed]]
ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=https://catalogue.aodn.org.au:443/geonetwork/srv/api/records/32807bb0-43cd-11dc-972b-00188b4c0af8&rft.title=Owner Advantage in the fiddler crab, Uca mjoebergi. Do owners win more contests than floaters because they have a mechanical advantage?&rft.identifier=https://catalogue.aodn.org.au:443/geonetwork/srv/api/records/32807bb0-43cd-11dc-972b-00188b4c0af8&rft.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 was designed to determine if owner advantage in the fiddler crab Uca mjoebergi, is due to a mechanical advanatage. Possible advantages come from the ability of the owner to utilise the burrow when fighting. For example, owners can retreat into their burrow and block the entrance using the 'flat-claw' defence. In addition to this, fiddler crabs may also gain advantage by using the burrow shaft during fights, producing greater leverage for their enlarged claw. This was tested by pitching fights between prior owners and resident owners with either their burrow blocked or open. Owners with unblocked burrows won 88% of contests, and those with blocked burrows won 38% of contests. This is a significance difference and infers that owners have a strong mechanical advantage.Maintenance and Update Frequency: notPlannedStatement: Contests were documented between prior owners and territory owners fighting with and without the use of their burrow. Floaters were created by removing owners from their burrows and releasing them onto the mudflat. Burrows were blocked by sliding a metal blade across the burrow entrance 0.5-1.5cm below the surface of the mudflat, immediately before the fight. As a control the metal blade was slid under the mud but stopped short of the burrow in those fights denoted as unblocked. The metal blade used in these manipulations was attached to the end of a 1.5m long wooden pole. The pole allowed us to perform the manipulation from a distance and avoid scaring crabs during fights. Major claw length (manus+pollex) and carapace width of each male were measured to the nearest 0.1mm using dial callipers. Fight duration was timed in the field using a handheld stopwatch and recorded to the nearest 0.01s.Statement: 35 fights were documented in total. 18 fights were documented between floaters and owners with their burrow blocked. 17 fights were documented between floaters and owners with their burrow unblocked. 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 fight duration and phases 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 (condition, OB=owners burrows blocked, OUB=control-owners burrows not blocked), winner, cara (intruder carapace width - mm), chel (inturder cheliped / claw length - mm), ocara (owner carapace width - mm), ochel (owner cheliped / claw length -mm), dura (duration of fight - seconds), sizediff (size difference between owner and intruder claws - mm).&rft.creator=Fayed, Sarah &rft.creator=Backwell, Patricia, Dr &rft.date=2007&rft.coverage=130.830175,-12.408046 130.830189,-12.408232 130.830413,-12.408210 130.830349,-12.407976 130.830175,-12.408046&rft.coverage=westlimit=130.5; southlimit=-13; eastlimit=131; northlimit=-12&rft.coverage=westlimit=130.5; southlimit=-13; eastlimit=131; northlimit=-12&rft.coverage=uplimit=0; downlimit=0&rft.coverage=uplimit=0; downlimit=0&rft_rights=Creative Commons Attribution 2.5 Australia License http://creativecommons.org/licenses/by/2.5/au/&rft_rights=The citation in a list of references is: citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data accessed at (add http link).&rft_rights=Please contact Sarah Fayed for access to the data.&rft_subject=biota&rft_subject=Biosphere | Ecological Dynamics | Competition&rft_subject=Biosphere | Ecological Dynamics | Dominance&rft_subject=COMMUNITY STRUCTURE&rft_subject=EARTH SCIENCE&rft_subject=BIOSPHERE&rft_subject=ECOLOGICAL DYNAMICS&rft_subject=COMMUNITY DYNAMICS&rft_subject=CRUSTACEANS&rft_subject=BIOLOGICAL CLASSIFICATION&rft_subject=ANIMALS/INVERTEBRATES&rft_subject=ARTHROPODS&rft_subject=Fiddler crabs&rft_subject=Uca mjoebergi&rft_subject=28960043&rft_subject=Owner Advantage&rft.type=dataset&rft.language=English Access the data
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The citation in a list of references is: citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data accessed at (add http link).

Please contact Sarah Fayed for access to the data.

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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 was designed to determine if owner advantage in the fiddler crab Uca mjoebergi, is due to a mechanical advanatage. Possible advantages come from the ability of the owner to utilise the burrow when fighting. For example, owners can retreat into their burrow and block the entrance using the 'flat-claw' defence. In addition to this, fiddler crabs may also gain advantage by using the burrow shaft during fights, producing greater leverage for their enlarged claw. This was tested by pitching fights between prior owners and resident owners with either their burrow blocked or open. Owners with unblocked burrows won 88% of contests, and those with blocked burrows won 38% of contests. This is a significance difference and infers that owners have a strong mechanical advantage.

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Maintenance and Update Frequency: notPlanned
Statement: Contests were documented between prior owners and territory owners fighting with and without the use of their burrow. Floaters were created by removing owners from their burrows and releasing them onto the mudflat. Burrows were blocked by sliding a metal blade across the burrow entrance 0.5-1.5cm below the surface of the mudflat, immediately before the fight. As a control the metal blade was slid under the mud but stopped short of the burrow in those fights denoted as unblocked. The metal blade used in these manipulations was attached to the end of a 1.5m long wooden pole. The pole allowed us to perform the manipulation from a distance and avoid scaring crabs during fights. Major claw length (manus+pollex) and carapace width of each male were measured to the nearest 0.1mm using dial callipers. Fight duration was timed in the field using a handheld stopwatch and recorded to the nearest 0.01s.
Statement: 35 fights were documented in total. 18 fights were documented between floaters and owners with their burrow blocked. 17 fights were documented between floaters and owners with their burrow unblocked. 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 fight duration and phases 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 (condition, OB=owners burrows blocked, OUB=control-owners burrows not blocked), winner, cara (intruder carapace width - mm), chel (inturder cheliped / claw length - mm), ocara (owner carapace width - mm), ochel (owner cheliped / claw length -mm), dura (duration of fight - seconds), sizediff (size difference between owner and intruder claws - mm).

Notes

Credit
Funded by The Ecological Society of Australia
Credit
Funded by The Australian Research Council (ARC)
Credit
The Australian National University (ANU)
Purpose
To determine if owner advantage in the fiddler crab Uca mjoebergi, is due to a mechanical advanatage.

Issued: 06 08 2007

Data time period: 2006-09-28 to 2006-12-30

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130.83018,-12.40805 130.83019,-12.40823 130.83041,-12.40821 130.83035,-12.40798 130.83018,-12.40805

130.830294,-12.408104

131,-12 131,-13 130.5,-13 130.5,-12 131,-12

130.75,-12.5

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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global : 637bba50-417e-11dc-aefb-00188b4c0af8

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  • global : 32807bb0-43cd-11dc-972b-00188b4c0af8