Abstracts

IAA22 Book of Abstracts (PDF)

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LIST OF MEETING ABSTRACTS

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Oral | Posters


Oral Presentations

 

 

Day: 2, Session: 3, Talk: 1

Assessing Crayfish Habitat Requirements: A Proposed Method for Determining Habitat Breadth in Lotic Ecosystems

CHRISTOPHER A. TAYLOR and Christopher J. Rice

Lotic ecosystems in the central and eastern United States can be highly variable in habitat structure, ranging from shallow riffles to deep pools. These same ecosystems harbor a highly endemic and threatened crayfish fauna. Understanding habitat requirements for rare species is fundamental for effective conservation, yet habitat descriptions for many of these species rely solely on data from easily accessed sampling locations. We tested a new sampling method for collecting the narrowly endemic Coldwater Crayfish (Faxonius eupunctus) in the southern Missouri Ozarks by utilizing SCUBA in deep, largely non-wadeable pools. Our methods allowed for unbiased and repeatable sampling within and across sites and for the collection of rigorous data on crayfish density and habitat associations. By combining our proposed pool sampling method with wadable riffle sampling, we expanded the known habitat requirements for the Coldwater Crayfish. Data from pool sampling increased known suitable ranges for temperature and substrate size for the species. Our work also found agreement between both habitat types for physcial habitat variables exhibiting significant relationships with Coldwater Crayfish density. Using mulitple sampling methods has long been known to increase the accuracy of community inventory sampling given differences in microhabitat use by community members. Our work demonstrates that employing multiple sampling methods can increase the accuracy of habitat requirements for rare crayfish species.

 

 

Day: 2, Session: 4, Talk: 3

The Life History of Cambarus veteranus Faxon 1914 (Decapoda: Cambaridae) in the Clear Fork of the Guyandotte River, WV, USA

NICOLE SADECKY and Zachary J. Loughman

Cambarus veteranus Faxon, 1914 (Guyandotte River Crayfish), is an endangered, narrow endemic, residing in just two streams in the southern coalfields of West Virginia. A life history study was initiated for C. veteranus in Clear Fork of the Guyandotte River, Wyoming County, West Virginia to gather basic life history information needed for future conservation efforts. Monthly collections began June 2017 and continued through May 2018. Two 400-meter stream reaches were designated as life history study sites with two different 100-meter sub-reaches sampled each month. Specimens, regardless of species, were collected, sexed, and molt stage determined. Preliminary results suggest an importance of water temperature on crayfish capture with December yielding considerably higher capture rates of C. veteranus in comparison to other species collected. Form I males are ever present and reach their highest density in early winter. Pre-glaired females reached their highest densities in October and December with glaired females present nearly every month. A single ovigerous female was collected, bearing just two stage 4 juveniles, during the November sampling event. Three ovigerous females bearing stage 4 juveniles were subsequently collected during the March sampling event, thus suggesting overwintering with young. Molting events were observed between September and October with pre-molting individuals present in September and freshly molted individuals present in October. Additionally, molting events occurred in March with pre-molting individuals present as well as freshly molted individuals and in May with the majority of the population observed in the soft or fresh molt state. Providing life history information for C. veteranus will assist in conservation efforts and possible repatriation of C. veteranus in the future. Additionally, life history information for C. veteranus can be compared to closely related species that are often used as a surrogate for C. veteranus in captive rearing studies.

 

 

Day: 5, Session: 2, Talk: 3

Impact of Limb Loss via Autotomy and Regeneration on Crayfish Behavior and the Added Effect of Predation.

LUC ARNAUD DUNOYER, Makayla Dean, Jeremy Van Cleve and Ashley Seifert

Through inter and intra-specific interactions crayfish can lose appendages by autotomizing their chelipeds to escape predation or mortality incurred during competition for mates, shelter, or food (Wood and Wood 1932; Bliss 1960; McVean 1982). While autotomy may provide an immediate advantage, regeneration of the lost limb may temporarily limit access to shelter, food, and the ability to find a mate (Kuris and Mager 1975, Sekkelsten 1988, Davenport et al. 1992, Abelló et al. 1994, Smith 1995). We hypothesized that crayfish (Procambarus clarkii) should avoid open exposure during appendage regeneration to avoid interactions where they would be at a competitive disadvantage. A pilot study we conducted showed us that, in a drought situation when no shelter was provided, all unmanipulated crayfish burrowed whereas autotomized crayfish made a depression at best. However, crayfish preferred to hide in a shelter rather than burrowing up to completely avoiding burrowing when missing a cheliped in presence of a shelter. Finally, crayfish spent more time in a shelter when provided one and this was exacerbated by autotomy. Hence, when exposed to conspecific predation cues, crayfish should hide in their burrow, seek available shelters, or leave the water to avoid predators altogether. In addition, crayfish regenerating one of their chelipeds should avoid predators altogether by leaving the water when exposed to conspecific predation cues because they can neither defend themselves efficiently nor efficiently burrow to avoid predation. To test our hypothesis, we proposed to examine the effect of limb autotomy on crayfish behaviors alone or in the presence of simulated predation using a potent chemical cue (i.e., crunched crayfish in water; Gherardi et al. 2011). We used 15-gallon aquaria with a mud bank on one side and a water pool on the other side. We observed crayfish (unmanipulated or autotomized and regenerating) alone or exposed to predator cues for a week at a time. First, burrowing behaviors was monitored daily (number and type: 0 = no burrow, 1 = depression, 2 = burrow, 3 = partial chimney, 4 = chimney). Second, each night was recorded using infrared cameras. Video recordings are used to determine the time spent outside of the water by crayfish overnight (when crayfish are active) as well as the type of behavior in which they engage (walking, resting, or burrowing). We predict a significant effect of regenerative status on crayfish burrowing behavior as measured by less complex burrow morphologies as well as less time spent outside the water for regenerative compared to unmanipulated crayfish. Similarly, we also predict a significant effect of predation cues on crayfish burrowing behavior as measure by more time spent outside the water in presence of crunched conspecific cues in the water. Finally, we predict a significant interaction between regenerative status and predator cues as measured by a behavioral change from regenerative crayfish in presence of crunched conspecific cues in the water (more time spent outside the water) compared to unmanipulated crayfish unexposed to predator cues. At the time of this abstract submission we just started data recording.

 

 

Day: 5, Session: 4, Talk: 1

Origin and Speciation of the Marbled Crayfish

FRANK LYKO

Marbled crayfish are a globally expanding population of parthenogenetically reproducing freshwater crayfish. They are closely related to the sexually reproducing slough crayfish, Procambarus fallax, which is native to the southeastern United States. However, reproductive incompatibility and substantial genetic differences suggest that the marbled crayfish should be considered an independent species (Procambarus virginalis). We have recently established a draft assembly of the marbled crayfish genome. We are now using comparative whole-genome sequencing to clarify the origin and speciation of marbled crayfish and I will discuss our available data.


 

Poster Presentations

 

 

POSTER 54

Crayfishes of the Potomac River Basin in Pennsylvania

AUDREY M. SYKES, David A. Lieb and Zachary J. Loughman

Arnold Ortmann was the first zoologist to critically review the crayfishes of Pennsylvania in the late 1800’s. Resultant of his work, Ortmann published The Crawfishes of Pennsylvania and The Crawfishes of Western Pennsylvania, two seminal works that are still relevant to this day. While extensive sampling in eastern Pennsylvania has occurred over the past two decades, western Pennsylvania’s crayfishes have received little scientific attention since Ortmann’s efforts. To rectify this dearth of information, intensive sampling of western Pennsylvania was initiated in the summer of 2014. This effort has been continuous for the past four years throughout the area using Ortmann’s work as a reference point in determining what constituted native fauna assemblage and the presence of invasive species. The ultimate goal of this project is to document both the native and invasive fauna of the Potomac Watershed in Pennsylvania. The historic faunal assemblage consists of Faxonius obscurus, Faxonius limosus, and Cambarus bartonii. Two invasive species, Faxonius rusticus and Faxonius virilis, have been reported in the Potomac Watershed downstream in Maryland. Pennsylvania’s portion of the Potomac Watershed will be sampled and reported in May of 2018. Over 100 sites will be sampled utilizing a protocol developed for the greater WPA Crayfish Survey by the West Liberty University’s Crayfish Conservation Lab. At each site, ten seine hauls will be employed in 125-meter stream reach, where the best available habitat will be surveyed first, followed by mediocre, and finally subpar habitat. In addition to a standard WPA Crayfish Datasheet, a Qualitative Habitat Evaluation Index Form (QHEI) will be completed at each site. This data will be used in the determination of habitat covariates associated with each species presence in the Potomac Watershed. All animals collected will be vouchered and assessed into the West Liberty University Astacology Collection.

 

 

POSTER 68

Gene Expression in the Crayfish Endocuticle

JERONIMO REYES-OLMEDO, Christian Kim, Trevor Dacus and Paul R. Cabe

Few genomic resources exist for any crayfish families and species despite their high species diversity, importance in freshwater ecosystems, and economic importance in aquiculture. The lack of such resources limits many areas of study, including phylogenetic relationships, local adaptation, and gene expression. We report on an exploratory study of transcripts abundantly expressed in the endocuticle tissues of Cambarus crayfish. For this work, mRNA was extracted from endocuticle tissues and copied to cDNA using reverse-transcriptase PCR. This pool of PCR products was fragmented and prepared for Illumina sequencing, yielding more than seven million paired end reads (150 base pairs each end). The sequence reads were assembled into putative transcripts using the Trinity software pipeline, and the transcripts ranked by abundance in the cDNA sample using both Sailfish and Salmon software tools. The most abundant transcripts were identified using DNA and/or protein BLAST searching. The transcripts include both well-known and unidentified gene sequences.

 

 

POSTER 69

The Life History of Cambarus robustus

GREGORY A. MYERS, David J. Foltz II., Emmy M. Delekta and Zachary J. Loughman

Crayfishes are the third most imperiled taxa in North America and are valuable keystone species in freshwater ecosystems. Cambarus veteranus is a narrow endemic in West Virginia recently listed by the U.S. Fish and Wildlife service as endangered. Cambarus robustus is a common species of crayfish that's closely related to C. veteranus, making it a suitable surrogate for investigations into the life history of C. veteranus. From June 2016 to July 2017, a collection of thirty individual C. robustus was made monthly. Gender, reproductive form, morphometric data (TCL, AbL, AbW, ChL, PaW), and natural history observations were recorded for each individual. When ovigerous females were encountered, they were placed in 80% EtOH and taken back to the lab where eggs were counted. A single ovigerous female was collected with a full load of eggs (n=94). Male C. robustus reached sexual maturity at 30.8mm TCL, and females reached sexual maturity at 37.3mm TCL. Brooding females were encountered invariably in a very specific microhabitat that may be pertinent to the conservation of this species. The results of this study will be useful for future life history studies of Cambarus, including imperiled taxa such as C. veteranus.

 

 

POSTER 72

Soft Serve: The Interactive Biology of the Queen Snake (Regina septemvittata) and Its Specialized Crayfish Prey in Northern West Virginia, USA.

DAN T. MEYER and Zachary J. Loughman

Coevolution of crayfishes and other animals is well documented in the literature. In North America, several species of vertebrates and invertebrates have been documented utilizing the burrows of various crayfish species. Crawfish Frogs (Lithobates areolatus), Hines Emerald Dragonflies (Somatochlora hineana), Kirtland's snakes (Clonophis kirtlandii) and Eastern Massasauga (Sistrurus catenatus) all utilize crayfish burrows during key if not all aspects of their life history and experience declines when burrowing crayfish colonies are destroyed. Several species of animals have also been documented as crayfish dietary specialists. Hellbender salamanders (Cryptobranchus) have long been known to rely heavily on crayfishes as forage. Several sports fish, including but not limited to black basses (Micropterus salmoides), sunfishes (Centrarchidae), catfishes (Siluriformes), and brown trout (Salmo trutta) also feed heavily upon crayfish during all facets of their life history. Arguably one of the most specialized of all North American crayfish dietary obligates could be the Queen Snake (Regina septemvittata). This small natricine snake occurs throughout the Appalachian, Piedmont, Midwest, and Ozarkian region of North America, and feeds exclusively on freshly molted crayfish. Queen Snakes have experienced precipitous declines over much of the western portion of their range, though seem to remain common throughout much of Appalachia. Historically, herpetologists studying Queen Snakes have studied the snake's movement patterns, reproductive biology, and life history, but have not delved deeply into this species feeding biology. Snakes will be captured and any food boluses present in snakes will be collected by palpation of the stomach region. Monthly crayfish life history sampling will be performed in our study streams to determine the molt frequency of Cambarus carinirostris and Faxonius obscurus, which co-occur and serve as forage for queen snakes. Snakes will be captured throughout their activity period and all regurgitated crayfish will be identified to species if possible, measured and weighed, and put into a designated size cohort based on crayfish life history sampling. Our goal is to determine if Queen Snakes rely heavily on a single species of crayfish, or rely on different crayfishes during peak molt periods, as well as determine if anyone size of crayfish experience predation over another. The ultimate outcome of this research will be a better understanding of this predators interaction with it crayfish prey, and provide valuable information for its future conservation.


Oral Presentations from IAA22

Day 1

  
  
  

Poster Presentations

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