Journal of Insect Behavior

, Volume 32, Issue 3, pp 225–235 | Cite as

Intraspecific Variation in the Secretion and Morphology of the Scent Glands of a Neotropical Harvestman (Opiliones, Cosmetidae)

  • Amanda C. Albert
  • Victor R. TownsendJrEmail author
  • Monika C. Metro
  • Elizabeth A. Roberto
  • Maynard H. Schaus


Relatively little is known about intraspecific variation in the use of chemical defenses by cosmetid harvestmen. In this study, we investigated sexual and ontogenetic variation in the emission of secretions from the scent glands and the morphology of the ozopores of Erginulus clavotibialis, a Neotropical species from Belize. Most individuals (> 94%) did not secrete when seized by leg IV, however, when the body was subsequently grasped firmly with forceps, 76% of the harvestmen (n = 96) responded by releasing enteric fluid (clear, no odor) or secretions from the scent glands (reddish-brown, distinct odor), most commonly in the form of globules near the ozopores. Adults and penultimate nymphs rarely (less than 5% of all trials) exhibited leg dabbing, an unusual behavior generally associated with cosmetid harvestmen. Males released enteric fluid (without scent gland secretions) significantly more than females or nymphs. Nymphs emitted secretions from scent glands at a significantly greater frequency than males or females. Using SEM, we examined the ozopores and the dorsal processes of coxae I and II and found that the morphology of these structures varies between adults and nymphs but not between males and females. The openings of the ozopores of nymphs are circular and are not obscured by the dorsal posterior process of coxa I and the dorsal anterior process of coxa II. In contrast, adults have subtriangular ozopores that are difficult to observe without dissection because they are partially blocked by the dorsal processes of coxae I and II.


Belize Erginulus nymph ontogenetic ozopore secondary defense 



  1. Acosta LE, Poretti TI, Mascarelli PE (1993) The defensive secretions of Pachyloidellus goliath (Opiliones, Laniatores, Gonyleptidae). Bonn Zool Beitr 44:19–31Google Scholar
  2. Bowers MD (2003) Hostplant suitability and defensive chemistry of the Catalpa Sphinx Ceratomia catalpa. J Chem Ecol 29:2359–2367PubMedGoogle Scholar
  3. Caetano DS, Machado G (2013) The ecological tale of Gonyleptidae (Arachnida, Opiliones) evolution: phylogeny of a neotropical lineage of armoured harvestmen using ecological, behavioural and chemical characters. Cladistics 29:589–609Google Scholar
  4. Camarano S, González A, Rossini C (2006) Chemical defense of the ladybird beetle Epilachna paenulata. Chemoecology 16:179–184Google Scholar
  5. Carlson BE, Rowe MP (2009) Temperature and desiccation effects on the antipredator behavior of Centruroides vittatus (Scorpoines: Buthidae). J Arachnol 37:321–330Google Scholar
  6. Carlson BE, McGinley S, Rowe MP (2014) Meek males and fighting females: sexually-dimorphic antipredator behavior and locomotor performance is explained by morphology in bark scorpions (Centruroides vittatus). PLoS One 9. PubMedPubMedCentralGoogle Scholar
  7. Chelini M-C, Willemart RH, Hebets EA (2009) Costs and benefits of freezing behaviour in the harvestman Eumesosoma roeweri (Arachnida, Opiliones). Behav Proc 82:153–159Google Scholar
  8. Clawson RC (1988) Morphology of defense glands of the opilionids (daddy longlegs) Leiobunum vittatum and L. flavum (Arachnida: Opiliones: Palpatores: Phalangiidae). J Morphol 198:363–381Google Scholar
  9. Cokendolpher JC (1987) Observations on the defensive behaviors of a Neotropical Gonyleptidae (Arachnida, Opiliones). Revue Arachnologique 7:59–63Google Scholar
  10. Cokendolpher JC, Mitov PG (2007) Natural enemies. Harvestmen: the biology of Opiliones. Harvard University Press, Cambridge, pp 339–373Google Scholar
  11. Cook DR, Smith AT, Proud DN, Víquez C, Townsend VR Jr (2013) Defensive responses of Neotropical harvestmen to generalist invertebrate predators. Carib J Sci 47:333–343Google Scholar
  12. Dossey AT, Walse SS, Edison AS (2008) Developmental and geographical variation in the chemical defense of the walkingstick insect Anisomorpha buprestoides. J Chem Ecol 34:584–590PubMedGoogle Scholar
  13. Duffield RM, Olubajo O, Wheeler JW, Shear WA (1981) Alkylphenols in the defensive secretion of the Nearctic opilionid, Stygnomma spinifera. J Chem Ecol 7:445–452PubMedGoogle Scholar
  14. Edgar AL (1971) Studies on the biology and ecology of Michigan Phalangida (Opiliones). Misc Pub Mus Zool Univ Michigan 144:1–64Google Scholar
  15. Eggenberger F, Rowell-Rahier M (1993) Physiological sources of variation in chemical defense of Oreina gloriosa (Coleoptera: Chrysomelidae). J Chem Ecol 19:395–410PubMedGoogle Scholar
  16. Eisner T, Kluge F, Carrel JE, Meinwald J (1971) Defense of Phalangid: liquid repellent administered by leg dabbing. Science 173:650–652PubMedGoogle Scholar
  17. Eisner T, Jones TH, Hicks K, Silberglied RE, Meinwald J (1977) Quinones and phenols in the defensive secretions of Neotropical opilionids. J Chem Ecol 3:321–329Google Scholar
  18. Eisner T, Rossini C, González A, Eisner M (2004) Chemical defense of an opilionid (Acanthopachylus aculeatus). J Exp Biol 207:1313–1321PubMedGoogle Scholar
  19. Frankfater C, Tellez MR, Slattery M (2009) The scent of alarm: Onotogenetic and genetic variation in the osmeterial gland chemistry of Papilio glaucus (Papilionidae) caterpillars. Chemoecology 19:81–96Google Scholar
  20. García AF, Kury AB (2017) Taxonomic revision of the Andean harvestman genus Rhaucus Simon, 1879 (Arachnida, Opiliones, Cosmetidae). Zootaxa 4338:401–440PubMedGoogle Scholar
  21. Gnaspini P, Cavalheiro AJ (1998) Chemical and behavioral defenses of a Neotropical cavernicolous harvestman: Goniosoma spelaeum (Opiliones Laniatores, Gonyleptidae). J Arachnol 26:81–90Google Scholar
  22. Gnaspini P, Hara MR (2007) Defense Mechanisms. Harvestmen: The Biology of Opiliones, Cambridge, Harvard University Press, pp 374–399Google Scholar
  23. Gnaspini P, Rodrigues GCS (2011) Comparative study of the morphology of the gland opening area among Grassatores harvestmen (Arachnida, Opiliones, Laniatores). J Zool Syst Evol Res 49:273–284Google Scholar
  24. Goodnight ML, Goodnight CJ (1976) Observation on the systematics, development, and habits of Erginulus clavotibialis (Opiliones: Cosmetidae). Trans Amer Micros Soc 95:654–664Google Scholar
  25. Guffey CA (1998) Leg autotomy and its potential fitness costs for two species of harvestmen (Arachnida, Opiliones). J Arachnol 26:296–302Google Scholar
  26. Guffey CA (1999) Costs associated with leg autotomy in the harvestmen Leiobunum nigripes and Leiobunum vittatum (Arachnida, Opiliones). Can J Zool 77:824–830Google Scholar
  27. Hara MR, Gnaspini P (2003) Comparative study of the defensive behavior and morphology of the gland opening area among harvestmen (Arachnida, Opiliones, Gonyleptidae) under a phylogenetic perspective. Arthropod Struct Dev 32:257–275PubMedGoogle Scholar
  28. Hara MR, Cavalheiro AJ, Gnaspini P, Santos DYAC (2005) A comparative analysis of the chemical nature of defensive secretions of Gonyleptidae (Arachnida: Opiliones: Laniatores). Biochem Syst Ecol 33:1210–1225Google Scholar
  29. Harvey BD, Vanni KN, Shier DM, Grether GF (2017) Experimental test of the mechanism underlying sexual segregation at communal roosts of harvestmen (Prionostemma sp.). Ethol 123:516–525Google Scholar
  30. Higginson AD, Delf J, Ruxton GD, Speed MP (2011) Growth and reproductive costs of larval defence in the aposematic lepidopteran Pieris brassicae. J Anim Ecol 80:384–392PubMedGoogle Scholar
  31. Jones TH, Meinwald J, Hicks K, Einser T (1977) Characterization and synthesis of volatile compounds from the defensive secretions of some “daddy longlegs” (Arachnida: Opiliones: Leiobunum spp.). Proc Natl Acad Sci U S A 74:419–422PubMedPubMedCentralGoogle Scholar
  32. Jones CG, Hess TA, Whitman DW, Silk PJ, Blum MS (1986) Idiosyncratic variation in chemical defenses among individual generalist grasshoppers. J Chem Ecol 12:749–761PubMedGoogle Scholar
  33. Jones TH, Shear WA, Giribet G (2009) The chemical defenses of a stylocellid (Arachnida, Opiliones, Stylocellidae) from Sulawesi with comparisons to other Cyphophthalmi. J Arachnol 37:147–150Google Scholar
  34. Juberthie C (1976) Chemical defence in soil Opiliones. Rev Écol Biol Sol 13:155–160Google Scholar
  35. Machado G, Pomini AM (2008) Chemical and behavioral defenses of the Neotropical harvestman Camarana flavipalpi (Arachnida: Opiliones). Biochem Syst Ecol 36:369–376Google Scholar
  36. Machado G, Raimundo RLG, Oliveira PS (2000) Daily activity schedule, gregariousness, and defensive behavior in the Neotropical harvestmen Goniosoma longipes (Opiliones: Gonyleptidae). J Nat Hist 34:587–596Google Scholar
  37. Machado G, Bonato V, Oliveira PS (2002) Alarm communication: a new function for the scent-gland secretion in harvestmen (Arachnida: Opiliones). Naturwissenschaften 89:57–360Google Scholar
  38. Machado G, Carrera PC, Pomini AM, Marsaioli AJ (2005) Chemical defense in harvestmen (Arachnida: Opiliones): do benzoquinones deter invertebrate and vertebrate predators? J Chem Ecol 31:2519–2539PubMedGoogle Scholar
  39. Minch EW (1978) Daily activity patterns in the tarantula Aphonopelma chalcodes Chamberlin. Bull Br Arachnol Soc 4:231–237Google Scholar
  40. Moore MK, Townsend VR Jr (2019) Sexual variation in jet emissions from scent glands by Neotropical harvestmen (Opiliones, Cranaidae) from Trinidad. Arachnol 18:17–21Google Scholar
  41. Nazareth TM, Machado G (2015) Egg production constrains chemical defenses in a Neotropical arachnid. PLoS One:1–14. PubMedPubMedCentralGoogle Scholar
  42. Nime MF, Casanoves F, Mattoni CI (2016) Microhabitat use and behavior differ across sex-age classes in the scorpion Brachistosternus ferrugineus (Scorpiones: Bothriuridae). J Arachnol 44:235–244Google Scholar
  43. Osses F, Nazareth TM, Machado G (2008) Activity pattern of the Neotropical harvestman Neosadocus maximus (Opiliones, Gonyleptidae): sexual and temporal variations. J Arachnol 36:518–526Google Scholar
  44. Pasteels JM, Grégorie J-C, Rowell-Rahier M (1983) The chemical ecology of defense in arthropods. Annu Rev Entomol 28:263–289Google Scholar
  45. Pomini AM, Machado G, Pinto-da-Rocha R, Macías-Ordóñez R, Marsaioli AJ (2010) Lines of defense in the harvestman Hoplobunus mexicanus (Arachnida: Opiliones): Aposematism, stridulation, thanatosis, and irritant chemicals. Biochem Syst Ecol 38:300–308Google Scholar
  46. Roitberg BD (1992) Insect chemical ecology: an evolutionary approach. Chapman & Hall, New YorkGoogle Scholar
  47. Schaider MG, Raspotnig G (2009) Unusual organization of scent glands in Trogulus tricarinatus (Opiliones, Trogulidae): evidence for a non-defensive role. J Arachnol 37:78–83. CrossRefGoogle Scholar
  48. Schaider MG, Komposch C, Stabentheiner E, Raspotnig G (2011) Functional anatomy of scent glands in Paranemastoma quadripunctatum (Opiliones, Dyspnoi, Nemastomatidae). J Morphol 272:1182–1191PubMedGoogle Scholar
  49. Schaus MH, Townsend VR Jr, Illinik JJ (2013) Food choice of the Neotropical harvestman Erginulus clavotibialis (Opiliones: Laniatores: Cosmetidae). J Arachnol 41:219–221Google Scholar
  50. Segovia JMG, Hara MR, Pagoti G, Sannomiya M (2015) The scent glands of the Neotropical harvestman Discocyrtus pectnifemur: morphology, behavior and chemistry. J Chem Ecol 41:716–723PubMedGoogle Scholar
  51. Segovia JMG, Murayama GP, Willemart RH (2018) Sexual differences in weaponry and defensive behavior in a Neotropical harvestman. Curr Zool 2018:1–6. CrossRefGoogle Scholar
  52. Shear WA, Jones TH, Guidry HM, Derkarabetian S, Richart CH, Minor M, Lewis JT (2014) Chemical defense in opilionid infraorder Insidiatores: divergence in chemical defense between Triaenonychidae and Travunioidea and within travunioid harvestmen from eastern and western North America. J Arachnol 42:248–256Google Scholar
  53. Souza EDS, Willemart RH (2011) Harvest-ironman: heavy armature, and not its defensive secretions, protects a harvestman against a spider. Anim Behav 81:127–133Google Scholar
  54. Townsend VR Jr, Víquez C, VanZandt PA, Proud DN (2010) Key to the species of Cosmetidae (Arachnida, Opiliones) of Central America, with notes on penis morphology and sexual dimorphisms. Zootaxa 2414:1–26Google Scholar
  55. Townsend VR Jr, Classen L, Maloney TJ, Moore MK (2019) Stridulation by a cosmetid harvestman. J Arachnol 47:132–141Google Scholar
  56. Weller SJ, Jacobson NL, Conner WE (1999) The evolution of chemical defences and mating systems in tiger moths (Lepidoptera: Arctiidae). Biol J Linn Soc 68:557–578Google Scholar
  57. Whitman DW, Jones CG, Blum MS (1992) Defensive secretion production in lubber grasshoppers (Orthoptera: Romaleidae): influence of age, sex, diet and discharge frequency. Ann Entomol Soc Am 85:96–102Google Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of BiologyVirginia Wesleyan UniversityVirginia BeachUSA

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