Males missing their sexually selected weapon have decreased fighting ability and mating success in a competitive environment

  • Zachary EmbertsEmail author
  • Colette M. St. Mary
  • Tyler J. Herrington
  • Christine W. Miller
Original Article


Intraspecific competition over access to females has led to a large diversity of animal weapons. Generally, the relative size (and presence) of these weapons is positively correlated with mating success, as individuals with the largest weapons often obtain most of the mates. Despite their importance, individuals in some species can lose their weapons. For example, a crab’s claw can be dropped to escape life-threatening situations and a beetle’s horn can break if it exceeds its mechanical limit. Previous research has shown that individuals missing their weapons are less successful at male-male competition, but few studies have investigated how weapon loss translates to changes in mating behavior and mating success. Here, we investigated how weapon loss affected fighting ability and mating success in the leaf-footed cactus bug Narnia femorata Stål (Hemiptera: Coreidae). In this study, males who lost their sexually selected weapons fought in the same manner as intact males, but were five times less likely to establish dominance. Despite this decrease in dominance, 34% of the weaponless males were still able to access females, and the lack of weaponry did not affect a female’s willingness to mate. Still, weapon loss ultimately decreased mating success by 37% in a competitive environment.

Significance statement

Sexually selected weapons are important for securing access to mates. Thus, it is often assumed that the permanent loss of a sexually selected weapon dramatically reduces, or even eliminates, an individual’s ability to secure matings. In our study, we tested this commonly held assumption. We found that weapon loss decreased both fighting ability and mating success. The observed difference in mating success was not due to female rejection, but instead was likely due to competitive male interactions. These results provide us with a better understanding of the costs associated with permanently losing a sexually selected weapon.


Autotomy Fighting behavior Male-male competition Mating behavior Sexual selection 



The authors would like to thank the anonymous reviewers, A. Mortensen, C. Howard, L. Cirino, L. Taylor, P. Allen, and R. Kimball for their insightful discussions and/or feedback that led this manuscript to take its current form. We would also like to thank undergraduate researchers I. Meirom and P. Skelly for their help in collecting data. This research was supported by the National Science Foundation grants IOS-1553100 and IOS-0926855 to CWM.

Compliance with ethical standards

Ethical approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

Supplementary material

265_2018_2494_MOESM1_ESM.docx (43 kb)
ESM 1 (DOCX 42 kb)


  1. Abello P, Warman CG, Reid DG, Naylor E (1994) Chela loss in the shore crab Carcinus maenas (Crustacea: Brachyura) and its effect on mating success. Mar Biol 121:247–252. CrossRefGoogle Scholar
  2. Allen PE, Miller CW (2017) Novel host plant leads to the loss of sexual dimorphism in a sexually selected male weapon. Proc R Soc Lond B 284:20171269. CrossRefGoogle Scholar
  3. Anderson (1994) Sexual selection. Princeton University Press, PrincetonGoogle Scholar
  4. Arnott G, Elwood RW (2009) Assessment of fighting ability in animal contests. Anim Behav 77:991–1004. CrossRefGoogle Scholar
  5. Bateman PW, Fleming PA (2006) Sex, intimidation and severed limbs: the effect of simulated predator attack and limb autotomy on calling and emergence behaviour in the field cricket Gryllus bimaculatus. Behav Ecol Sociobiol 59:674–681. CrossRefGoogle Scholar
  6. Berzins IK, Caldwell RL (1983) The effect of injury on the agonistic behavior of the Stomatopod, Gonodactylus Bredini (manning). Mar Behav Physiol 10:83–96. CrossRefGoogle Scholar
  7. Booksmythe I, Milner RNC, Jennions MD, Backwell PRY (2009) How do weaponless male fiddler crabs avoid aggression? Behav Ecol Sociobiol 64(3):485–491. CrossRefGoogle Scholar
  8. Cirino LA, Miller CW (2017) Seasonal effects on the population, morphology and reproductive behavior of Narnia femorata (Hemiptera: Coreidae). Insects 8:13. CrossRefPubMedCentralGoogle Scholar
  9. Cooper WE (2007) Compensatory changes in escape and refuge use following autotomy in the lizard Sceloporus virgatus. Can J Zool 85:99–107. CrossRefGoogle Scholar
  10. Emberts Z, Miller CW, Kiehl D, St. Mary CM (2017) Cut your losses: self-amputation of injured limbs increases survival. Behav Ecol 28:1047–1054. CrossRefPubMedPubMedCentralGoogle Scholar
  11. Emberts Z, St. Mary CM, Miller CW (2016) Coreidae (Insecta: Hemiptera) limb loss and autotomy. Ann Entomol Soc Am 109:678–683. CrossRefGoogle Scholar
  12. Emlen D (1997) Alternative reproductive tactics and male-dimorphism in the horned beetle Onthophagus acumiatus (Coleoptera: Scarabaeidae). Behav Ecol Sociobiol 41:335–341CrossRefGoogle Scholar
  13. Emlen D (2008) The evolution of animal weapons. Annu Rev Ecol Evol Syst 39:387–413.
  14. Gillespie SR, Scarlett Tudor M, Moore AJ, Miller CW (2014) Sexual selection is influenced by both developmental and adult environments. Evolution 68:3421–3432. CrossRefPubMedGoogle Scholar
  15. Gross MR (1996) Alternative reproductive strategies and tactics: diversity within sexes. Trends Ecol Evol 11:92–98. CrossRefPubMedGoogle Scholar
  16. Hamilton WD, Zuk M (1982) Heritable true fitness and bright birds: a role for parasites? Science 218:384–387. CrossRefPubMedGoogle Scholar
  17. Herreid CF, Full RJ (1986) Locomotion of hermit crabs (Coenobita Compressus) on beach and treadmill. J Exp Biol 120:283–296Google Scholar
  18. Hill GE (1991) Plumage coloration is a sexually selected indicator of male quality. Nature 350:337–339CrossRefGoogle Scholar
  19. Hoadley L (1937) Autotomy in the brachyuran, Uca pugax. Biol Bull 73:155–163CrossRefGoogle Scholar
  20. Hsu Y, Earley RL, Wolf LL (2006) Modulation of aggressive behaviour by fighting experience: mechanisms and contest outcomes. Biol Rev Camb Philos Soc 81:33–74. CrossRefPubMedGoogle Scholar
  21. Joseph PN, Emberts Z, Sasson DA, Miller CW (2018) Males that drop a sexually-selected weapon grow larger testes. Evolution 72:113–122CrossRefPubMedGoogle Scholar
  22. McCullough EL (2014) Mechanical limits to maximum weapon size in a giant rhinoceros beetle. Proc Biol Sci 281:20140696. CrossRefPubMedPubMedCentralGoogle Scholar
  23. McCullough EL, Tobalske BW, Emlen DJ (2014) Structural adaptations to diverse fighting styles in sexually selected weapons. Proc Natl Acad Sci 111:14484–14488. CrossRefPubMedGoogle Scholar
  24. Morrell LJ, Lindström J, Ruxton GD (2005) Why are small males aggressive? Proc R Soc Lond B 272:1235–1241. CrossRefGoogle Scholar
  25. Morris MR (1998) Female preference for trait symmetry in addition to trait size in swordtail fish. Proc R Soc Lond B 265:907–911. CrossRefGoogle Scholar
  26. Morris MR, Gass L, Ryan MJ (1995) Assessment and individual recognition of opponents in the pygmy swordtails Xiphophorus nigrensis and X. Multilineatus. Behav Ecol Sociobiol 37:303–310CrossRefGoogle Scholar
  27. Neil SJ (1985) Size assessment and cues: studies of hermit crab contests. Behaviour 92:22–38CrossRefGoogle Scholar
  28. Nolen ZJ, Allen PE, Miller CW (2017) Seasonal resource value and male size influence male aggressive interactions in the leaf footed cactus bug, Narnia femorata. Behav Process 138:1–6. CrossRefGoogle Scholar
  29. O’Neill DJ, Cobb JS (1979) Some factors influencing the outcome of shelter competition in lobsters (Homarus americanus). Mar Behav Physiol 6:33–45. CrossRefGoogle Scholar
  30. de Oliveira DN, Christofoletti RA, Barreto RE (2015) Feeding behavior of a crab according to Cheliped number. PLoS One 10:e0145121. CrossRefPubMedPubMedCentralGoogle Scholar
  31. Parker G (1974) Assessment strategy and the evolution of animal conflicts. J Theor Biol 47:223–243CrossRefPubMedGoogle Scholar
  32. Payne RJH, Pagel M (1996) Escalation and time costs in displays of endurance. J Theor Biol 183:185–193CrossRefGoogle Scholar
  33. Procter DS, Moore AJ, Miller CW (2012) The form of sexual selection arising from male-male competition depends on the presence of females in the social environment. J Evol Biol 25:803–812. CrossRefPubMedGoogle Scholar
  34. R Core Team (2016) R: a language and environment for statistical computing. Vienna, AustriaGoogle Scholar
  35. Smith LD (1992) The impact of limb autotomy on mate competition in blue crabs Callinectes sapidus Rathbun. Oecologia 89:494–501CrossRefPubMedGoogle Scholar
  36. Somjee U, Miller CW, Tatarnic NJ, Simmons LW (2018) Experimental manipulation reveals a trade-off between weapons and testes. J Evol Biol 31:57–65CrossRefPubMedGoogle Scholar
  37. Stoks R (1999) Autotomy shapes the trade-off between seeking cover and foraging in larval damselflies. Behav Ecol Sociobiol 47:70–75. CrossRefGoogle Scholar
  38. Swaddle JP, Cuthill IC (1994) Female zebra finches prefer male with symmetric chest plumage. Proc R Soc Lond B 258:267–271. CrossRefGoogle Scholar
  39. Yasuda C, Suzuki Y, Wada S (2011) Function of the major cheliped in male-male competition in the hermit crab Pagurus nigrofascia. Mar Biol 158:2327–2334. CrossRefGoogle Scholar
  40. 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. CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of BiologyUniversity of FloridaGainesvilleUSA
  2. 2.Entomology and Nematology DepartmentUniversity of FloridaGainesvilleUSA

Personalised recommendations