DOI: 10.5061/dryad.qjq2bvqqq
title: A survey of Cambarus crayfish and their symbiotic branchiobdellidans, Sinking Creek, Newport, VA, USA 2017-2018

description: Crayfish throughout the holarctic are found in association with an order
 of worms known as branchiobdellidans. This relationship has been confirmed
 as a cleaning symbiosis in several species. The Conhaway crayfish,
 Cambarus appalachiensis, is a species of crayfish endemic to the New River
 Basin in Virginia and West Virginia. We studied a population of C.
 appalachiensis in Sinking Creek in Newport, VA from March 2017 until
 February 2018. We collected morphological data and quantified the
 branchiobdellidan communities on 986 individuals, and kept note of egg
 brooding and young of year throughout the study period. The life cycle of
 C. appalachiensis was found to be similar to other large-bodied species of
 Cambarus crayfish. Molting occurred throughout the year, peaking in the
 months of April and September. This molting served as a disturbance effect
 to the symbiotic branchiobdellidan community and reset community assembly.
 The worm communities on larger, recently molted crayfish more closely
 resembled the less diverse communities on smaller crayfish. Most worms on
 recently molted crayfish were ones that we know are early colonizers. This
 survey provides the first life history information on a newly described
 species of Cambarus crayfish and provides both seasonal data on its
 branchiobdellidan associates and one of the first empirical examples of
 host ontogeny acting as a disturbance on a symbiotic community.
description: We sampled the crayfish <em>Cambarus
 appalachiensis</em>, previously <em>C. sciotensis</em>
 (Loughman et al. 2017), bimonthly in Sinking Creek at the Newport
 Recreation Area in Newport, VA (37.303096°N, 80.485522°W) from March 2017
 until February 2018. The stream reach we chose to sample had multiple
 riffles and pools, and covered a broad range of crayfish habitats. We
 sampled crayfish from these varied microhabitats across the stream reach
 using dip nets, totaling 986 crayfish captures during our study. Our
 monthly sample sizes ranged from 53 to 104 crayfish. After measuring the
 physical properties of the crayfish and symbiont identification (detailed
 below), crayfish were returned to the stream and deposited downstream of
 the collection site to reduce the chance of resampling the same
 crayfish. Crayfish were separated from each other at
 the stream to prevent symbiont dispersal between sampled crayfish,
 transported from the stream to a laboratory, and stored live in the
 refrigerator separated from each other in repurposed hardware parts
 organizers, termed “crayfish hotels”. We measured physical attributes of
 the crayfish, including the carapace length (the distance from the rostrum
 to the separation between the cephalothorax and the abdomen of the
 crayfish), the chelae length, the palm width (the width of the chelae at
 the widest point), the palm length, (length of the chelae up to the
 joint), the blotted wet mass, the sex, and the reproductive form. We
 measured total carapace length (a standard measure of crayfish size) of
 sampled crayfish, and determined carapace hardness using manual palpations
 to assess exoskeleton elasticity and a visual assessment of carapace
 fouling. This assessment of carapace hardness (exoskeleton hardening
 stage, or EHS) was used as a proxy for time since last molt, with a
 carapace graded as EHS 0/1 (soft exoskeleton), EHS 2 (hard exoskeleton,
 but with some elasticity and limited fouling), or EHS 3 (very hard and
 fouled exoskeleton, no elasticity) (Castillo-Escrivà et al. 2013). A score
 of EHS 0/1 indicated that the crayfish had molted very recently, a score
 of EHS 2 indicated the crayfish had molted somewhat recently, and a score
 of EHS 3 indicated that it had been some time since the crayfish
 molted. We counted branchiobdellidan symbionts on the
 exterior of living crayfish using a low-magnification dissecting
 microscope. Symbiont counts were performed by a single observer throughout
 the study to prevent interobserver error. Counting symbionts on living
 crayfish had the advantage of allowing us to see the symbiont location on
 the host, and how the distribution of symbionts on the crayfish changed
 with the makeup of the symbiont community. We identified 13466 symbionts
 on the exoskeletons of the sampled crayfish according to a key developed
 for the crayfish and symbionts in southwestern Virginia (Hobbs et al.
 1967). The branchiobdellidan symbiont community present on the exoskeleton
 of the crayfish in this population consisted of four species:
 <em>Cambarincola ingens</em> (Hoffman 1963),
 <em>Cambarincola fallax</em> (Hoffman 1963),
 <em>Ankyrodrilus koronaeus</em> (Holt 1965), and
 <em>Pterodrilus alcicornus</em> (Moore 1894). The location of
 each branchiobdellidan symbiont on the host crayfish was also noted using
 a classification based on the one used by Brown et al. (2002).
 Brown BL, Creed RP, Dobson WE (2002) Branchiobdellid annelids and
 their crayfish hosts: are they engaged in a cleaning symbiosis? Oecologia
 132(2):250-255 Castillo-Escrivà A, Mestre A, Monrós JS,
 Mesquita-Joanes F (2013) Population dynamics of an epibiont Ostracoda on
 the invasive red swamp crayfish Procambarus clarkii in a western
 Mediterranean wetland. Hydrobiologia 714(1):217-228
 Hobbs HH Jr, Holt PC, Walton M (1967) The crayfishes and their
 epizootic ostracod and branchiobdellid associates of the Mountain Lake,
 Virginia, region. Proceedings of the United States National Museum
 123(3602):1-84 Hoffman RL (1963) A revision of the
 North American annelid worms of the genus Cambarincola (Oligochaeta:
 Branchiobdellidae). Proceedings of the United States National Museum
 114(3470):271-371 Holt PC (1965) On Ankyrodrilus, a new
 genus of branchiobdellid worms (Annelida). Virginia Journal of Science
 16:9-21 Loughman ZJ, Welsh SA, Thoma RF (2017) Cambarus
 (C.) appalachiensis, a new species of crayfish (Decapoda: Cambaridae) from
 the New River Basin of Virginia and West Virginia, USA. Zootaxa
 4243(3):432-454 Moore JP (1894) Pterodrilus, a
 remarkable discodrilid. Proceedings of the Academy of Natural Sciences of
 Philadelphia 46:449-454 Reynolds JD
 (2002) Growth and reproduction. In: Holdich DM (ed) Biology of Freshwater
 Crayfish. Wiley-Blackwell, Hoboken, NJ, pp 152-191
description: # A Survey of Cambarus crayfish and their Symbiotic Branchiobdellidans,
 Sinking Creek, Newport, VA, USA 2017-2018
 [https://doi.org/10.5061/dryad.qjq2bvqqq](https://doi.org/10.5061/dryad.qjq2bvqqq) ## Sampling Methods The location of each branchiobdellidan symbiont on the host crayfish was also noted. They are described as follows, including the letter used to denote a branchiobdellidan found at that location in the dataset: the ventral margin of the crayfish carapace, or within 5 mm of the ventral margin (**a**); the dorsal surface of the chelae (**b**); the walking legs (**c**); the anterior section of the carapace including the rostrum (excluding a), defined as the section anterior to the primarty transverse structure on the cephalothorax (**d**), the posterior section of the carapace (excluding a and f), defined as the section behind the primary transverse suture on the cephalothorax (**e**); within the margins of the areola (**f**); the dorsal surface of the abdomen (**g**), the dorsal surface of the telson and uropods (**h**), the ventral surface of the chelae (**i**), the mouthparts (**j**), the antennae and antennae and antennules (**k**); the ventral surface of the telson and uropods (**l**); the ventral surface of the abdomen (**m**); and the ventral surface of the cephalothorax (**n**). This classification was based on the one used by Brown et al. (2002). ## Description of Data Below are the variables and descriptions for the data in the file Sinking_Creek_Crayfish_and_Branchiobdellidan_Survey.csv, included in this repository. | Variable | Description | | :----------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Date | The date the host crayfish and associated branchiobdellidans were sampled (YYYY/MM/DD). | | Carapace Length (mm) | The distance from the rostrum to the separation between the cephalothorax and the abdomen of the crayfish, in mm. | | Chelae Length (mm) | The length of the largest chela of the crayfish, in mm. | | Palm Width (mm) | The width of the largest chela of the crayfish at the widest point, in mm. | | Palm Length (mm) | Length of the largest chela of the crayfish up to the joint, in mm. | | Abdomen Width (mm) | The width of the abdomen of the crayfish, in mm, taken only for females. | | Mass (g) | The blotted wet mass of the crayfish, in g. | | Sex (f/m) | The sex of the crayfish, as determined by the presence or absence of gonopods. | | Reproductive Form (I/II) | The reproductive form of male crayfish, determined through an inspection of the gonopods. For female crayfish, this field was left blank. | | Carapace Hardness (EHS) | A visual assessment of carapace hardness based on elasticity and fouling, either EHS 0/1 (soft exoskeleton), EHS 2 (hard exoskeleton with some fouling, but with some elasticity), or EHS 3 (very hard exoskeleton with lots of fouling, no elasticity). | | C. ingens | The number of *Cambarincola ingens* present on the carapace of the host crayfish. | | C. fallax | The number of *Cambarincola fallax* present on the carapace of the host crayfish. | | A. koronaeus | The number of *Ankyrodrilus koronaeus* present on the carapace of the host crayfish. | | P. alcicornus | The number of *Pterodrilus alcicornus* present on the carapace of the host crayfish. | | Cocoons | The number of branchiobdellidan cocoons present on the carapace of the host crayfish. | | C. ingens Location | The location of *Cambarincola ingens* on the host crayfish. See sampling methods for location descriptions. This field was left blank if no *C. ingens* were found on the host crayfish. | | C. fallax Location | The location of *Cambarincola fallax* on the host crayfish. See sampling methods for location descriptions. This field was left blank if no *C. fallax* were found on the host crayfish. | | A. koronaeus Location | The location of *Ankyrodrilus koronaeus* on the host crayfish. See sampling methods for location descriptions. This field was left blank if no *A. koronaeus* were found on the host crayfish. | | P. alcicornus Location | The location of *Pterodrilus alcicornus* on the host crayfish. See sampling methods for location descriptions. This field was left blank if no *P. alcicornus* were found on the host crayfish. | | Cocoon Location | The location of branchiobdellidan cocoons on the host crayfish. See sampling methods for location descriptions. This field was left blank if no cocoons were found on the host crayfish. |