Abstract
Physical traits such as body size and weapon size typically reflect an individual’s resource holding potential (RHP). During male–male contests, contestants use these traits to assess their own and their opponent’s RHP. However, the advertisement of RHP does not always predict contest outcome. Here, we examined whether assessment index (body size or weapon size [major cheliped size]) and assessment tactics (self or mutual) are predictors of outcome in male–male contests of the hermit crab Pagurus minutus. In experimental contests over guarded females, intruders did not escalate the contest when their major cheliped was smaller than their opponent’s, implying that intruders use mutual assessment based on weapon size when deciding whether to escalate a contest. After escalation, intruders succeeded in taking over females within a shorter period of time with increasing major cheliped size relative to their opponent’s. Overall, males with a major cheliped that was larger than their opponent’s were more likely to win the contest, although some intruders later stopped guarding the female they had taken over. The importance of relative weapon size after escalation indicates that mutual assessment was also used in this phase of male–male contests. Together, these results suggest that males of P. minutus use mutual assessment based on weapon size throughout male–male contests, and that weapon size is an honest index of RHP.
Significance statement
We examined whether assessment index (body or weapon size) and tactics (self or mutual) are predictors of outcome in male–male contests of the hermit crab Pagurus minutus. Intruders did not escalate contests when their major cheliped was smaller than their opponent’s, implying that mutual assessment based on weapon size was used to decide whether to escalate contests. After escalation, intruders succeeded in taking over females within a shorter period of time and were more likely to win with increasing weapon size relative to their opponent’s. The importance of relative weapon size after escalation indicated that mutual assessment was also used in this phase of contests. Together, these results suggest that males of P. minutus use mutual assessment based on weapon size throughout male–male contests, and that weapon size is an honest index of actual strength.
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References
Akaike H (1983) Information measures and model selection. Bull Int Stat Inst 44:277–291
Andersson M (1994) Sexual selection. Princeton University Press, Princeton
Arnott G, Elwood RW (2008) Information gathering and decision making about resource value in animal contests. Anim Behav 76:529–542
Arnott G, Elwood RW (2009) Assessment of fighting ability in animal contests. Anim Behav 77:991–1004
Arnott G, Elwood RW (2010) Signal residuals and hermit crab displays: flaunt it if you have it! Anim Behav 79:137–143
Backwell PRY, Christy JH, Telford SR, Jennions MD, Passmore NI (2000) Dishonest signalling in a fiddler crab. Proc R Soc Lond B 267:719–724
Bee MA, Perrill SA, Owen PC (2000) Male green frogs lower the pitch of acoustic signals in defense of territories: a possible dishonest signal of size? Behav Ecol 11:169–177
Briffa M (2008) Decisions during fights in the house cricket, Acheta domesticus: mutual or self assessment of energy, weapons and size? Anim Behav 75:1053–1062
Briffa M, Sneddon LU (2007) Physiological constraints on contest behaviour. Funct Ecol 21:627–637
Briffa M (2013) Contests in crustaceans: assessments, decisions and their underlying mechanisms. In: Hardy ICW, Briffa M (eds) Animal contests. Cambridge University Press, New York, pp. 86–112
Clutton-Brock TH (1982) The functions of antlers. Behaviour 79:108–124
Copeland DL, Levay B, Sivaraman B, Beebe-Fugloni C, Earley RL (2011) Metabolic costs of fighting are driven by contest performance in male convict cichlid fish. Anim Behav 82:271–280
Cox DR (1972) Regression models and life-tables. J R Stat Soc B 34:187–220
Eddy SL, Wilburn DB, Chouinard AJ, Doty KA, Kiemnec-Tyburczy KM, Houck LD (2016) Male terrestrial salamanders demonstrate sequential mate choice based on female gravidity and size. Anim Behav 113:23–29
Elwood RW, Pothanikat RME, Briffa M (2006) Honest and dishonest displays, motivational state and subsequent decisions in hermit crab shell fights. Anim Behav 72:853–859
Emlen DJ (2008) The evolution of animal weapons. Annu Rev Ecol Evol Syst 39:387–413
Enquist M, Leimar O (1983) Evolution of fighting behaviour: decision rules and assessment of relative strength. J Theor Biol 102:387–410
Enquist M, Leimar O (1987) Evolution of fighting behaviour: the effect of variation in resource value. J Theor Biol 127:187–205
Enquist M, Leimar O, Ljungberg T, Mallner Y, Segerdahl N (1990) A test of the sequential assessment game: fighting in the cichlid fish Nannacara anomala. Anim Behav 40:1–14
Fawcett TW, Mowles SL (2013) Assessments of fighting ability need not be cognitively complex. Anim Behav 86:e1–e7
Fuxjager MJ, Marler CA (2010) How and why the winner effect forms: influences of contest environment and species differences. Behav Ecol 21:37–45
Goshima S, Kawashima T, Wada S (1998) Mate choice by males of the hermit crab Pagurus filholi: do males assess ripeness and/or fecundity of females? Ecol Res 13:151–161
Hack MA, Thompson DJ, Fernandes DM (1997) Fighting in males of the autumn spider, Metellina segmentata: effects of relative body size, prior residency and female value on contest outcome and duration. Ethology 103:488–498
Hardy ICW, Briffa M (2013) Animal contests. Cambridge University Press, New York
Herrel A, Podos J, Huber SK, Hendry AP (2005) Bite performance and morphology in a population of Darwin’s finches: implications for the evolution of beak shape. Funct Ecol 19:43–48
Hsu Y, Lee S, Chen M, Yang S, Cheng K (2008) Switching assessment strategy during a contest: fighting in killifish Kryptolebias marmoratus. Anim Behav 75:1641–1649
Hughes M (1996) Size assessment via a visual signal in snapping shrimp. Behav Ecol Sociobiol 38:51–57
Hughes M (2000) Deception with honest signals: signal residuals and signal function in snapping shrimp. Behav Ecol 11:614–623
Imafuku M (1986) Sexual discrimination in the hermit crab Pagurus geminus. J Ethol 4:39–47
Jennings DJ, Gammell MP, Carlin CM, Hayden TJ (2004) Effect of body weight, antler length, resource value and experience on fight duration and intensity in fallow deer. Anim Behav 68:213–221
Johannesson K, Saltin SH, Duranovic I, Havenhand JN, Jonsson PR (2010) Indiscriminate males: mating behaviour of a marine snail compromised by a sexual conflict? PLoS One 5:e12005
Ladich F (1998) Sound characteristics and outcome of contests in male croaking gouramis (Teleostei). Ethology 104:517–529
Lailvaux SP, Reaney LT, Backwell PRY (2009) Dishonest signalling of fighting ability and multiple performance traits in the fiddler crab Uca mjoebergi. Funct Ecol 23:359–366
Mariappan P, Balasundaram C, Schmitz B (2000) Decapod crustacean chelipeds: an overview. J Biosci 25:301–313
Marler CA, Walsberg G, White ML, Moore M (1995) Increased energy expenditure due to increased territorial defense in male lizards after phenotypic manipulation. Behav Ecol Sociobiol 37:225–231
Maynard Smith J, Harper D (2003) Animal signals. Oxford University Press, New York
Moore JC, Obbard DJ, Reuter C, West SA, Cook JM (2008) Fighting strategies in two species of fig wasp. Anim Behav 76:315–322
Moore JC, Obbard DJ, Reuter C, West SA, Cook JM (2009) Male morphology and dishonest signalling in a fig wasp. Anim Behav 78:147–153
Morrell LJ, Bakwell PRY, Metcalfe NB (2005) Fighting in fiddler crabs Uca mjoebergi: what determines duration? Anim Behav 70:653–662
Okamura S, Goshima S (2010) Indirect female choice mediated by sex pheromones in the hermit crab Pagurus filholi. J Ethol 28:323–329
Parker GA (1974) Assessment strategy and the evolution of fighting behaviour. J Theor Biol 47:223–243
Pratt AE, McLain DK, Lathrop GR (2003) The assessment game in sand fiddler crab contests for breeding burrows. Anim Behav 65:945–955
Prenter J, Elwood RW, Taylor PW (2006) Self-assessment by males during energetically costly contests over precopula females in amphipods. Anim Behav 72:861–868
R Core Team (2013) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna
Riechert MS, Gerhardt HC (2013) Gray tree frogs, Hyla versicolor, give lower-frequency aggressive calls in more escalated contests. Behav Ecol Sociobiol 67:795–804
Rohwer S (1982) The evolution of reliable and unreliable badges of fighting ability. Am Zool 22:531–546
Searcy WA, Nowicki S (2005) The evolution of animal communication: reliability and deception in signaling systems. Princeton University Press, Princeton
Sigurjónsdóttir H, Parker GA (1981) Dung fly struggles: evidence for assessment strategy. Behav Ecol Sociobiol 8:219–230
Small J, Cotton S, Fowler K, Pomiankowski A (2009) Male eyespan and resource ownership affect contest outcome in the stalk-eyed fly, Teleopsis dalmanni. Anim Behav 78:1213–1220
Sneddon LU, Huntingford FA, Taylor AC (1997) Weapon size versus body size as predictor of winning in fights between shore crab, Carcinus maenas (L.) Behav Ecol Sociobiol 41:237–242
Suzuki Y, Yasuda C, Takeshita F, Wada S (2012) Male mate choice and male-male competition in the hermit crab Pagurus nigrofascia: importance of female quality. Mar Biol 159:1991–1996
Tanikawa D, Yasuda C, Suzuki Y, Wada S (2012) Effects of male size and mate quality on male-male contest in the hermit crab Pagurus filholi. Jap J Benthol 67:15–19
Taylor PW, Elwood RW (2003) The mismeasure of animal contests. Anim Behav 65:1195–1202
Tedore C, Johnsen S (2012) Weaponry, color, and contest success in the jumping spider Lyssomanes viridis. Behav Process 89:203–211
Tsai YJJ, Barrows EM, Weiss MR (2014) Pure self-assessment of size during male-male contests in the parasitoid wasp Nasonia vitripennis. Ethology 120:816–824
Wada S, Goshima S, Nakao S (1995) Reproductive biology of the hermit crab Pagurus middendorffii Brandt (Decapoda: Anomura: Paguridae). Crust Res 24:23–32
Wada S, Ito A, Mima A (2007) Evolutionary significance of prenuptial molting in female Pagurus hermit crabs. Mar Biol 152:1263–1270
Wilson RS, Angilletta MJ Jr (2015) Dishonest signaling during aggressive interactions: theory and empirical evidence. In: Irschick DJ, Briffa M, Podos J (eds) Animal signaling and function: an integrative approach. Wiley Blackwell, Hoboken, pp. 205–227
Wilson RS, Angilletta MJ Jr, James RS, Navas C, Seebacher F (2007) Dishonest signals of strength in male slender crayfish (Cherax dispar) during agonistic encounters. Am Nat 170:284–291
Yamanoi T, Yoshino K, Kon K, Goshima S (2006) Delayed copulation as a means of female choice by the hermit crab Pagurus filholi. J Ethol 24:213–218
Yasuda CI, Koga T (2016) Do weaponless males of the hermit crab Pagurus minutus give up contests without escalation? Behavior of intruders that lack their major cheliped in male-male contests. J Ethol 34:249–254
Yasuda C, Takeshita F, Wada S (2012) Assessment strategy in male-male contests of the hermit crab Pagurus middendorffii. Anim Behav 84:385–390
Yasuda CI, Matsuo K, Wada S (2014) Rapid regeneration of the major cheliped in relation to its function in male-male contests in the hermit crab Pagurus middendorffii. Plankton and Benthos Res 9:122–131
Yoshino K, Ozawa M, Goshima S (2004) Effects of shell size fit on the efficacy of mate guarding behaviour in male hermit crabs. J Mar Biol Assoc UK 84:1203–1208
Yoshino K, Koga T, Oki S (2011) Chelipeds are the real weapon: cheliped size is a more effective determinant than body size in male-male competition for mates in a hermit crab. Behav Ecol Sociobiol 65:1825–1832
Acknowledgments
We are grateful to the two referees for their extensive comments and contributions, which helped to improve the manuscript. This study was financially supported by a JSPS Research Fellowship for Young Scientists (No. 25-2149 and 15J07721) to CY.
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Yasuda, C.I., Koga, T. Importance of weapon size in all stages of male–male contests in the hermit crab Pagurus minutus . Behav Ecol Sociobiol 70, 2175–2183 (2016). https://doi.org/10.1007/s00265-016-2221-0
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DOI: https://doi.org/10.1007/s00265-016-2221-0