Primary Burrowers Research Articles

A new burrowing crayfish of the genus Fallicambarus Hobbs, 1969 (Decapoda: Cambaridae) from the Red River Drainage of the southcentral United States.

A new primary burrowing crayfish, Fallicambarus schusteri, is described from the Red River drainage of extreme southeastern Oklahoma and southwestern Arkansas and is placed in the subgenus Fallicambarus. The species occurs in roadside ditches that seasonally flood and have silt and silt-loam dominated soils. Falllicambarus schusteri differs from all other members of the genus Fallicambarus in possessing a thin gradually tapering central projection and a wide triangular cephalic process on the first pleopod of form I males, a sufflamen on the cheliped, and an antennal scale that is widest at its midpoint.

A night of devastation: Natural and life history observations of an en-masse single night collection of Fallicambarus devastator.

Due to their fossorial tendencies, primary burrowing crayfish are the most difficult behavioral group of crayfish to study in-situ. In this study we elucidated both natural and life history aspects and intraspecific behaviors from a collection of 111 individual Fallicambarus devastator collected in Angelina County, Texas, on the night of May 15th, 2015. We also intend to emphasize the importance of environmental cues on collection success. Significant amounts of precipitation occurred during the days prior to 15 May 2015, resulting in the majority of burrows to be flooded on the day of collection. All animals were collected either traversing the landscape or captured at the portal of their burrow. Behaviors observed included excavation, respiration, feeding, and interspecific interactions. The majority of animals observed were adults, with juveniles noticeably absent on the surface. Life history observations included evidence of synchronous alteration to reproductive form in males, as well as sexually-dependent chelae morphometric ratios. Fallicambarus devastator meristically displayed sexual dimorphism between form I male and female chelae, with form I chelae having longer propodus length and greater palm widths, compared to the squamous and shorter chelae of females. Understanding the significance of studying these animals in favorable conditions is of paramount importance to the quality of future primary burrowing crayfish research.

Western Pennsylvania's primary burrowing crayfish: Distributional survey and determination of conservation status.

Arnold Ortmann, one of the nations first crayfish biologists, conducted crayfish surveys in the late 1800’s and early 1900’s across western Pennsylvania. Unique for the time was Ortmann’s inclusion of primary burrowing crayfishes. Primary burrowing crayfish utilize subterranean burrows for all facets of their ecology, and are rarely encountered outside their burrows. Urbanization, extractive industries, and the genesis of industry have all occurred across western Pennsylvania since Ortmann’s initial surveys. We visited all of Ortmann’s historic sites to determine if burrowing crayfish still occur throughout the region following the past century of environmental change. Furthermore, crayfish have been recognized recently as one of North America’s most imperiled group of animals. Resultants of this, our efforts will lead to the determination of conservation baselines for each burrowing crayfish species occurring in the region.

English

Abstract The Oconee burrowing crayfish, Cambarus truncatus, is endemic to the Oconee River watershed in central Georgia. Very little is known about this primary burrower’s life history or distribution. To gather life history data, a non-invasive study was conducted using Norrocky burrowing crayfish traps and burrowing crayfish nets at Balls Ferry State Park in Toomsboro, Georgia. Crayfish were captured, measured, tagged, and released to determine growth rate, reproductive stage, and association with physiochemical factors. Thirty-six specimens were captured during the study of which twenty-five were tagged and released. Ten of the individuals were recaptured multiple times. Form I males were found in the months of February, March, May, October, and November. Female glair gland activity was present from February – May, when four in-berry females were captured; females held an average of 28 eggs. Glair gland activity peaked again during the months of October and November. Cambarus truncatus exhibited a growth rate of about 1 mm in total carapace length per molt until plateauing at about 34 mm total carapace length. The largest specimen collected was a female measuring 34.6 mm in total carapace length. The known distribution of C. truncatus was increased from 15 to 26 localities during this study, and now encompasses six counties within the Oconee River watershed.

English

Abstract Spatial distributions of South Carolina crayfish were geo-referenced for over 3900 museum and collection records. Collection site records are not evenly distributed across the state; some parts of the state are poorly represented while other parts have a disproportionate number of collection records. Currently, 38 described species in five genera occur in the state of which eight are endemic species and one an introduced species. Cambarus latimanus and Procambarus troglodytes were the two most widely distributed species while the four Distocambarus species have the narrowest distributions. Most of the records of Cambarus were from above the fall line, whereas, Procambarus records occurred mostly below the fall line; the exceptions were for the primary burrowers C. diogenes and C. reflexus and the stream dwelling P. spiculifer. Crayfish species were rarely restricted to single river systems or watershed units. The 27% of South Carolina crayfish species considered in the greatest conservation need included all four Distocambarus species, four Cambarus species and two Procambarus species. Conservation status of the South Carolina crayfish will require updating because of the potential taxonomic problems of species complexes, new species descriptions and limited distribution records for some species.

Comparative Homing Behaviors in Two Species of Crayfish, Fallicambarus Fodiens and Orconectes Rusticus

AbstractHoming behaviors are seen across the animal kingdom, with the magnitude and scale of these movements varying to a great degree. Invertebrates, such as crayfish, prove to be excellent models for comparative research, with relatively simple nervous systems that have been extensively studied combined with a rich behavioral repertoire that has been well documented. Here we explore whether two crayfish species (a primary burrower and a tertiary burrower) can home to artificial burrows and if so, whether their homing abilities differ. The two species of crayfish, Orconectes rusticus and Fallicambarus fodiens, were examined for their ability to home to artificial burrows in a laboratory setting. Animals were placed in a homing arena, motivated to search by the presence of food, and subsequently return to the burrows. The movements of each individual crayfish were digitized and analyzed for changes in walking speed, velocity and heading angle relative to burrows, total distance travelled and path turning angles. Crayfish of both species successfully returned home, although F. fodiens had a higher homing success rate than O. rusticus. Detailed kinematic analysis showed that walking speeds almost doubled during homing to burrows and heading angles were significantly closer to zero than on the outward journeys for both species. Path turning angles were significantly lower for O. rusticus than for F. fodiens. These findings indicate that these species of crayfish can successfully home without the visual landmark of burrow chimneys and that the primary burrower (F. fodiens) appears to be more successful with straighter return paths. The differences in these two species to home and the underlying mechanisms of homing may be due to the differences in burrow use with primary burrowers showing more efficient homing than tertiary burrowers.

Life history and physical observations of primary burrowing crayfish (Decapoda: Cambaridae) Cambarus (Lacunicambarus) diogenes and Cambarus (Tubericambarus) polychromatus

Primary burrowing crayfish make up 15% of total crayfish species, but account for 32% of those imperiled. Primary burrowers are also much less studied as compared to secondary and tertiary burrowers. The purpose of this study was to observe the annual life cycles, and morphometric and morphological characteristics of two primary burrowing crayfish species: Cambarus (Lacunicambarus) diogenes Girard, 1852 and C. (Tubericambarus) polychromatus Thoma et al., 2005. Sampling occurred adjacent to two streams near Troy, AL, using hand excavation at one-month intervals from February 2011 to March 2012. A total of 195 C. diogenes (sex ratio = 1.3) and 194 C. polychromatus (sex ratio = 0.85) were collected. For a given size, C. diogenes had a broader carapace than C. polychromatus ( p< 0.001), and males had larger chelae than females for both species (p = 0.01 and p = 0.001, respectively). Minimum carapace length at sexual maturity (smallest form I) was 32.7 mm for C. diogenes males, 41.2 mm for C. diogenes females, 27.4 mm for C. polychromatus males, and 32.2 for C. polychromatus females. The proportion of form I males for both species increased in summer and remained at an increased level through winter, though C. polychromatus males remained reproductively active longer than C. diogenes. Females of both species were reproductively active only in winter except for one form I C. polychromatus female. Four ovigerous C. diogenes and three ovigerous C. polychromatus were collected in March, and five young of the year of C. polychromatus were found in burrows in June, July, and September.

Crayfishes of the Apalachicola Ravines, Northern Florida: A Search for the Fireback Crayfish,Cambarus pyronotus

The series of steep, wooded ravines along the eastern side of the Apalachicola River in Gadsden and Liberty counties, FL, is recognized for its rich biodiversity. Little recent information is available on crayfishes of this unique ecosystem. During surveys conducted from 1939–1941, 5 taxa, including one undescribed species (now Cambarus pyronotus [Fireback Crayfish]), were recorded. No crayfish studies were conducted in the Apalachicola Ravines in the ensuing 60 years, and the conservation status of C. pyronotus remained unknown. From June 1999–February 2002, we surveyed the Apalachicola Ravines to determine distributional limits and stream-by-stream occurrence of C. pyronotus and evaluate its conservation status in relation to the regional system of protected lands. We recorded 8 species of crayfishes, including 4 primary burrowers and 4 aquatic species. Members of each of these 2 groups exhibited distinct microgeographic and microhabitat selection patterns, with several species showing non-overlapping microdistributions. We documented C. pyronotus from only 12 of 29 stream drainages surveyed, all within the middle region of the survey area, for a total range estimate of about 80 km2. Most of the inhabited streams within this small range occur on protected lands and include multiple habitable branches.

Life-History Observations, Environmental Associations, and Soil Preferences of the Piedmont Blue Burrower (Cambarus[Depressicambarus]harti) Hobbs

Cambarus (Depressicambarus) harti (Piedmont Blue Burrower) is a state-endangered primary burrowing crayfish found in highly organic soils associated with seepage areas only in Meriwether County, GA. As is the case with many native burrowing crayfishes, virtually nothing is known about the biology and ecology of this species. To help fill this gap, the current study provides information on population demographics, environmental correlates of activity, burrowing behavior, and habitat fidelity of C. harti. Field surveys from the type locality revealed that crayfish could be found throughout the year, with a near 3:1 ratio of female to male adults captured, an ovigerous female found in June, and the highest number of small juveniles found in August. Adults were not found together in burrows; however, juveniles were often found sharing the burrows of females. Burrowing activity was generally higher in the summer than winter, and also increased with receding groundwater levels. Based on observations and experiments with artificial burrowing chambers (ABCs), the burrows of C. harti followed a predictable form and were often capped with at least one chimney of seemingly deliberate construction. Total burrow area and mean chimney pellet diameter increased with crayfish size. It appeared that C. harti will burrow in other soils, but displays a strong affinity to its type-locality soils, particularly below groundwater level. Observations from a communal ABC revealed that adults use burrows to brood young and will share burrows with other adults for a period of time, possibly during burrow construction and/or times of disturbance, but eventually tend to segregate to solitary occupancy. Taken together, these data offer insight into the biology and ecology of this highly endemic and elusive animal that will be useful for management and conservation efforts and provide much-needed scientific information about burrowing crayfishes in general.

Aggressiveness and life underground: the case of burrowing crayfish

This study compared aggression in two morphologically similar neotropical burrowing crayfishes, Parastacus pilimanus, a primary burrower, and Parastacus brasiliensis, a secondary burrower. Intraspecific pairs were formed, with a maximum 15% difference in carapace and chelae length within each pair. Pairs were allowed to interact for 20 min, during which they were recorded, and the agonistic behaviour was then analyzed throughout these recordings. The species were compared with respect to mean bout duration, first bout duration, number of bouts, latency period, frequency of highly aggressive behaviours, frequency of low aggressive behaviours, as well as the number of approaches, antennal whips and chelae punches. The proportion of interactions that resulted in formation of a clear hierarchy was also compared. Parastacus brasiliensis was the more aggressive species, showing statistically higher values for all parameters except latency, as well as number of bouts and antennal whips (among winners); while P. pilimanus performed more chelae punches. In general terms, both species showed low aggression (due to the absence of clearly escalated fights and other behaviours), which differs from the pattern expected for crayfish. The formation of dominance relationships was more frequent in P. pilimanus than in P. brasiliensis. Due to possible pressure for co-existence and reduced competition for resources, the burrowing habit appears to influence aggression, with the more fossorial species being less aggressive. It is assumed that these differences are related to: (i) phylogenetic distance from the open water species; (ii) the burrowing habitat and the related morphological adaptations and (iii) a reduced need to acquire and defend resources other than their burrows.

Unexpected discovery of Parastacus pugnax (Decapoda, Parastacidae) in a lotic environment of central-southern Chile

Parastacus pugnax has been classified by many authors as a primary burrower that inhabits underground waters in semi-marshland areas, located at a distance from permanent water bodies. This article reports the discovery of specimens of this species in the bed of the “Quillay” stream, in the locality of “La Suerte”, Los Angeles district of central-southern Chile. Information is provided with respect to the number and size of specimens collected, the physico-chemical characteristics of the water and the flow volume, depth and width of the stream. The lack of evidence supporting the previous recordings of P. pugnax in lotic waters is discussed, as is its classification as a primary burrower. A comparative analysis is made of the physico-chemical characteristics of the stream waters and also of the importance of this discovery in terms of P. pugnax culture potential in captivity.

Occupancy rates of primary burrowing crayfish in natural and disturbed large river bottomlands

ABSTRACT Among crayfish, primary burrowing species are the least understood ecologically. Many primary burrowing crayfish inhabit floodplains where forested landscapes have been fragmented by agricultural, industrial, or residential uses. In this study, site occupancy rates (ψ) were modeled for two primary burrowing crayfish, Fallicambarus fodiens (Cottle, 1863) and Cambarus thomai Jezerinac, 1993, from Ohio and Kanawha river floodplains in West Virginia, U.S.A. Fallicambarus fodiens is one of West Virginia's rarest crayfish, while C. thomai is prevalent in most wetlands along both river floodplains. Occupancy rate modeling incorporated four environmental covariates (forest age, soil type, tree frequency, and land use). Based on presence/absence data, forests with tree ages > 100 years (ΔQAICc = 0) and sites with loam soils (ΔQAICc = 1.80) were most likely to harbor F. fodiens populations. For C. thomai, several models were supported owing to model selection uncertainty, but those with the land use covari...

The Wyoming carbon underground storage project: Geologic characterization of the Moxa Arch and Rock Springs Uplift

The Wyoming carbon underground storage project: Geologic characterization of the Moxa Arch and Rock Springs Uplift

The occurrence of primary burrowing crayfish in terrestrial habitat

A researcher’s perception of a target species’ landscape strongly influences the design of habitat studies conducted at broad spatial scales. Consequently, researcher-dependent perceptions may misguide conservation efforts. Although the life histories of some crayfish (i.e., primary burrowers) are centered on a fossorial existence independent of surface water, all North American crayfish are viewed in an aquatic context. This paradigm restricts the range of habitats that are typically sampled and managed for crayfish conservation. This study used presence/absence of the primary burrower Distocambarus crockeri at 137 locations within the Long Cane Ranger District of the Sumter National Forest, South Carolina, USA, to model the habitat association of the species across a GIS-based landscape. Logistic regression indicated that D. crockeri presence was most strongly associated with a terrestrial habitat defined by a set of morphologically similar soils located along ridge tops. Furthermore, the species was negatively associated with aquatic habitats such as streams and floodplains. The results indicate that D. crockeri is a terrestrial habitat specialist and should be modeled and managed at the landscape as a terrestrial organism. When viewed as a subset of the total United States cambarid fauna, primary burrowers are disproportionately imperiled. Primary burrowers comprise only 15% of the total crayfish fauna, while they account for 32% of those crayfish ranked critically imperiled. Habitat loss and an aquatic bias that restricted sampling to aquatic and semi-aquatic habitats might explain the group’s disproportionate imperilment.

To stay or to leave? Decision rules for partner species relocation in two symbiotic pairs of desert beetles

Four nocturnal Kalahari desert tenebrionid beetles live in closely associated species pairs. The larger member of each pair, Parastizopus and Gonopus, are the primary burrowers while their smaller associates, Eremostibes and Herpiscius, inhabit the burrows with them and feed on detritus the larger beetles carry in. During summer drought, the two large species have different emergence times, surface activity patterns (vagilities) and different probabilities that burrows will be reoccupied before sunrise or remain empty for longer periods. Because their partners leave the burrows, the smaller species must make a decision either to stay in the expectation of a burrow being reinhabited, or leave and locate a new partner. The vagility and burrow fidelity of the associating species were studied using marked individuals in free-living populations. Field inclusion/exclusion experiments to test what influences the decision process showed that neither continual partner presence nor food induced the smaller beetles to remain. Different percentages, depending on species, left overnight. For both associates, these proportions corresponded exactly to the probability that the burrow would not be inhabited by their partner species the next day. Neither species predicted the probability of burrow reoccupation after a short vacancy and adopted a “waiting” strategy.

Parabiosis and its Proximate Mechanisms in Four Kalahari Desert Tenebrionid Beetles

AbstractFour nocturnal desert tenebrionids with complete ecological niche overlap as adults form daytime aggregations in burrows in species pairs, Eremostibes with Parastizopus and Herpiscius with Gonopus. Parastizopus and Gonopus were the primary burrowers, the associations being initiated by the smaller partners. Association was not dependent on differences in temperature preference between species nor only on the ecological conditions the larger beetles provided. Partner species were preferred over other tenebrionids of the same size. The proximate segregating mechanism was avoidance of the non‐partner by the smaller species. Avoidance was odour‐mediated in Eremostibes, which also showed an equal odour‐based preference for conspecifics and Parastizopus. Odour profile similarity between the two was hypothesized as the mechanism permitting coexistence. An odour‐mediated preference for Gonopus or conspecifics could not be shown for Herpiscius, nor was Parastizopus odour avoided. Here, a higher relative humidity in inhabited burrows was suggested as the proximate factor promoting association. A possible advantage of aggregation for desert tenebrionids is discussed.