title: Variation in venom yield and protein concentration of the centipedes Scolopendra polymorpha and Scolopendra subspinipes.
abstract: Venom generally comprises a complex mixture of compounds representing a non-trivial metabolic expense. Accordingly, natural selection should fine-tune the amount of venom carried within an animal's venom gland(s). The venom supply of scolopendromorph centipedes likely influences their venom use and has implications for the severity of human envenomations, yet we understand very little about their venom yields and the factors influencing them. We investigated how size, specifically body length, influenced volume yield and protein concentration of electrically extracted venom in Scolopendra polymorpha and Scolopendra subspinipes. We also examined additional potential influences on yield in S. polymorpha, including relative forcipule size, relative mass, geographic origin (Arizona vs. California), sex, time in captivity, and milking history. Volume yield was linearly related to body length, and S. subspinipes yielded a larger length-specific volume than S. polymorpha. Body length and protein concentration were uncorrelated. When considering multiple influences on volume yield in S. polymorpha, the most important factor was body length, but yield was also positively associated with relative forcipule length and relative body mass. S. polymorpha from California yielded a greater volume of venom with a higher protein concentration than conspecifics from Arizona, all else being equal. Previously milked animals yielded less venom with a lower protein concentration. For both species, approximately two-thirds of extractable venom was expressed in the first two pulses, with remaining pulses yielding declining amounts, but venom protein concentration did not vary across pulses. Further study is necessary to ascertain the ecological significance of the factors influencing venom yield and how availability may influence venom use.
authors.affiliation: Department of Earth and Biological Sciences, Griggs Hall #101, Loma Linda University, 24941 Stewart St., Loma Linda, CA 92350, USA. Electronic address: allenmcooper@gmail.com.
authors.forename: Allen M
authors.initials: AM
authors.lastname: Cooper
authors.affiliation: Department of Earth and Biological Sciences, Griggs Hall #101, Loma Linda University, 24941 Stewart St., Loma Linda, CA 92350, USA.
authors.forename: Gerad A
authors.initials: GA
authors.lastname: Fox
authors.affiliation: Department of Earth and Biological Sciences, Griggs Hall #101, Loma Linda University, 24941 Stewart St., Loma Linda, CA 92350, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Nelsen
authors.affiliation: Department of Earth and Biological Sciences, Griggs Hall #101, Loma Linda University, 24941 Stewart St., Loma Linda, CA 92350, USA.
authors.forename: William K
authors.initials: WK
authors.lastname: Hayes
mesh_terms: D000818:Animals; D001130:Arizona; D001180:Arthropod Venoms / Q000096:biosynthesis / Q000737:chemistry*; D001181:Arthropods / Q000378:metabolism / Q000502:physiology*; D049628:Body Size; D002140:California; D004558:Electric Stimulation; D005260:Female; D008297:Male; D011042:Poisons / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D013045:Species Specificity
chemical_list: D001180:Arthropod Venoms; D011042:Poisons; D011506:Proteins
keywords: Body size; Chilopoda; Electrical stimulation; Morphology; Scolopendromorpha; Venom extraction