POSTER 5

Mate Choice in Spiny-cheek Crayfish (Orconectes limosus, Rafinesque 1817): Females Prefer Males from the Same Population, Males not

Kubec J, Kouba A, Kozák P and Buřič M

Investigating of different effects on mate choice belong to major principles in behavioural and ecological studies. The mate choice is often based on recognition of conspecifics and social experiences (e.g. hierarchy, aggression or fighting), which play important roles in decision-making. In crayfish, it is known that females, which have large energy cost, are more choosy than males. We analysed mate selection of the spiny-cheek crayfish (Orconectes limosus) in the laboratory conditions. Our objective was to explore the effect of different origin of individuals (three geographically separated populations) on preference in mate choice. Both sexes were divided into triad groups (male with a familiar and unfamiliar female; female with a familiar and unfamiliar male). Our results suggest that spiny-cheek crayfish females choose mates from the familiar population, whereas males do not exhibit any specific preference between conspecifics from all. Our study offers information around reproductive behaviour that previous experience enables invertebrate females to easier decision making. While the males confirmed hypothesis about lesser selectivity. This study has the potential for future research on the largely overlooked field of mate choice in invertebrates.

POSTER 7

The stone crayfish in the czech republic: lost-and-found in last seven years

Vlach P, Fischer D and Svobodová J

Within the period 2012-2015, an intensive research concerning: 1. mapping the occurrence of stone crayfish; 2. monitoring of presently known populations; 3. an evaluation of ecological demands of this species, was carried out. This contribution focuses on newly described localities, losses of some populations, and populations affected by a dramatic decrease in population densities in some localities. Moreover, the contribution introduces a hypothesis or/and particular reasons for that decrease or extinction. The extinction in Úpor brook and Hýskovský brook has already been published; recently we have recorded the following losses: Zákolanský brook, Bertínský brook, Vlcí brook, Kornatický brook, Hrádecký brook, and Medvedí brook. Whereas the combination of crayfish plague and (probably) low water quality caused the total mortality in lower part of the Zákolanský brook, crayfish plague outbreak killed crayfish in Kornatický and Hrádecký brook in 2015. Conversely, there was a lethal concentration of BOD5 in Vlcí brook. Also dramatic droughts in 2015 influenced the population densities in Chocenický and Prešínský brook. The mass mortality in Klabava was caused by a combination of stream acidification and toxic metal accumulation. The reasons for other losses are mostly speculative. On the other hand, within the mapping campaign, we found more than 10 new populations of stone crayfish. Nevertheless, the newly recorded occurrences correspond with a present range of this species in the Czech Republic.

POSTER 8

Fine Structure of the Spermatozoon in Three Species of (Arthropoda: Crustacea: Decapoda) Cambarus robustus, Orconectes propinquus and Orconectes rusticus: A Comparative Biometrical Study

Yazicioglu B, Hamr P, Kozák P, Kouba A and Niksirat H

The ultrastructure of spermatozoa in three species of cambarid crayfish, including Cambarus robustus, Orconectes propinquus, and Orconectes rusticus were studied and compared with eight previously studied species from different crayfish families using morphological features and biometrical data. The ultrastructure of spermatozoa show a generally conserved pattern including an acrosome and nucleus in the anterior and posterior parts of the cell, respectively, radial arms that wrap around the nucleus, and the whole cell is enclosed by an extracellular capsule. The most outstanding morphological feature in spermatozoa of three studied cambarid crayfish is the crest-like protrusions in the anterior part of the acrosome that can be used as one of the features for distinguishing the members of this family. Results of biometrical data reveal that acrosome size in the representatives of Parastacidae are the smallest, while representatives of Astacidae show the biggest acrosome. The acrosome size in species belonging to Cambaridae occupy an intermediate position between the two other families of freshwater crayfish. In conclusion, a combination of morphological features and biometrical data of spermatozoa can provide an effective tool to distinguish different species of the freshwater crayfish.

POSTER 9

Metabolic Rate of Cambarellus montezumae (Crustacea: Cambaridae): Effects of Size and Seasonal Changes

Latournerié-Cervera JR, García-Padilla GM, and Estrada-Ortega AR

The measurement of metabolic rate is a key element of a species energy balance. The evaluation of respiratory metabolism in natural conditions, allows us to know the energy requirement of the animal for different processes including growth, activity, reproduction, among others. The objective of this study was to know the element (R) of the energy budget equation: C = P+R+F+U (IBP, 1968) in Cambarellus montezumae, during hot rainy season (May – August) and transitional months (September – October) in the area of study. Recently collected samples of crayfish (n=15) representing small, medium and large sizes of both sexes were employed in respirometry experiments, using a closed respirometer. The temperature and water quality were similar to the conditions of the sampling site. Two measurement periods were used: (noon and evening). Average routine metabolic rate was used for comparisons (QO₂: mg O₂/g. dry weight/h) and was converted to cal/g.dw/day using the Q_ox=3.31 cal/mgO₂ (Brafield & Solomon, 1972). Comparisons for size and month were made by ANOVA factorial (3 X 6) and Tukey test post hoc (p<0.05). Significant differences were obtained by month and size. QO₂ was similar between the months of the rainy season, with a temperature average range of (22.3 ± 1.6°C) and had a significant decrease (p<0.05) in October. Relationships of QO₂ – WW were calculated for all months using a potential model. We discuss results in relation to energy requirements of the species for growth and reproduction and its potential use for intensive management.

POSTER 12

Analysis of Abundance, Fecundity and Allometric Relationships from Cambarellus montezumae Females During an Annual Cycle

Latournerié-Cervera JR, García-Padilla GM, Estrada-Ortega AR and Arana-Magallón F

Cambarellus montezumae population at Xochimilco, Mexico City, is in serious problems of disappearance. This species was highly appreciated and it was regularly consumed as part of the diet of the Xochimilcas and Mexican people. Nowadays, crayfish is very scarce in this area. As a part of a collaboration research, UNAM and UAM universities have undertaken the project of assessment and rescue of native species in the area of Xochimilco. In this study, we analyze the female population of C. montezumae during an annual cycle. 42 berried females were collected in ten months of sampling (January – October). Abundance varied significantly by sampling month (p<0.05). 76.2% of females were collected during hot rainy season (April – August). Description and analysis of these females were made through: total and cephalothorax length, (TL and CTL). Large and width of abdomen, wet weight, ovigerous mass weight and number of eggs. Minimum, maximum and average values for TL, WW and number of eggs were: (28.31, 43.21, 34.5) mm, (0.58, 1.91, 0.99) g, and 13, 150 and 46.9 eggs respectively. Distributions of TL and WW were positive skewness. Allometric relationships were calculated for WW – TL (potential model, r²=0.93), CTL – TL (linear model, r²=0.86). Fecundity – TL was positive correlated (r=0.68, p<0.05). Also positive and significant correlations (p<0.05), were obtained for abdomen width and length – TL and female abundance – temperature. Ovigerous mass weight was higher on April and number of eggs per female was bigger on September. We discuss results in relation to scarcity of berried females, the decrease in the number of eggs per female, the size of first maturity, and anthropogenic impacts in the study area.

POSTER 15

Reproductive Cycle of the Marble Crayfish from an Established Population in Croatia

Cvitanić M, Hudina S and Maguire I

The marble crayfish (Procambarus fallax f. virginalis) is a relatively new non-indigenous crayfish species that has established populations in Europe. Until today, it is the only known decapod species with parthenogenetic reproduction. Established population of marble crayfish was recently discovered in a gravel pit in Northwest Croatia. Apart from parthenogenetic reproduction, the invasion success of this species stems from its early maturation, and higher fecundity compared to other crayfish species. Therefore, the aim of this study was to examine the year cycle of the marble crayfish in Croatia, and its potential (number of ovarian eggs) and realized fecundity (number of pleopodal eggs and juveniles). Our results show that all 140 examined individuals were reproductively active during the whole sampling period. Peaks of reproduction activity were recorded from September to November, when both individuals with pleopodal eggs or juveniles as well as individuals with ripe ovarian eggs were recorded. The smallest reproductively active female was 40.81 mm TL, while reproductive output increased with size (TL). The average number of ovarian eggs was 297. The average number of pleopodal eggs was 15% lower than the number of ovarian eggs, while number of juveniles attached to pleopods was reduced by 50% from ovarian egg count. This represents a lower brood loss compared to other crayfish species. Due to almost constant reproduction, early maturation and relatively high potential and realized fecundity in an established population in Croatia, the marble crayfish represents a major threat to the surrounding waterbodies and their native crayfish fauna.

POSTER 18

No Species Recognition Between Two Alien Crayfish Species?

Tricarico E, Coignet A and Souty-Grosset C

Crayfish rely on odours for finding a resource, detecting predators and recognizing species. Species that are not co-evolved could not chemically recognize each other. The red swamp crayfish Procambarus clarkii and the spinycheek crayfish Orconectes limosus, both native to North America where they occupy different areas, have coexisted in the “Parc Naturel Régional de la Brenne” (Centre Region, France) since 2007 but in different ponds. Behavioural observations were conducted in October 2014 and April 2015 to assess if P. clarkii and O. limosus are able to chemically recognize individuals of both sexes belonging to the same or other species. In experimental individual aquarium, records of behaviour of 20 Procambarus males and 20 Orconectes males were made of 3-min observation bouts for each of two sequential phases: (a) the “water” phase, following the introduction of 10 mL of well water, (b) the “smell” phase, following the introduction of 10 mL of well water conditioned by (1) P. clarkii male, (2) P. clarkii female, (3) O. limosus male and (4) O. limosus female odour. The time spent by each crayfish in locomotion and other activities (feeding, cleaning), and the time spent in one of three postures (raised, intermediate, or lowered) were recorded every 15 s. Crayfish seem able to recognize the conspecific of the same sex (males), and not the heterospecific, underlying the absence of species recognition in these two species that separately evolved.

POSTER 22

Positive Selection of Beautiful Invasives: Long-term Persistence and Bio-invasion Risk of Ornamental Crayfish

Chucholl C and Wendler F

Following a distinct peak interest to keep freshwater crayfish in home aquaria in the mid-2000s, the aquarium trade has become a novel introduction pathway for alien crayfish species in Central Europe. Here, we provide an update on the German ornamental crayfish trade approximately one decade after the `crayfish hype´ to explore the long-term implications in terms of bio-invasion risk. Specifically, species’ availability and potential invasiveness, as well as the determinants of availability were assessed. In July 2015, a total of 31 online shops offered 28 crayfish species, which represents a decline of 24% in species diversity compared to the late 2000s. In addition, the estimated rate of import of new species has considerably flattened and approaches pre-hype values (< 1 species · y^-1). However, the risk associated with the offered species, as assessed by a risk screening tool (FI-ISK), has not decreased compared to the late 2000s. Long-term availability in the trade (covering one decade) was primarily determined by bright coloration, the ability to reproduce under warm aquarium conditions, and a preference for lentic habitats. Species featuring such traits are likely to persist in the aquarium trade and include four high-risk species, most notably invasive and crayfish plague-carrying red swamp crayfish (Procambarus clarkii) and Marmorkrebs (Procambarus fallax f. virginalis). Persistent propagule pressure from aquaria has substantially contributed to the establishment of both species in Central Europe, stressing the need for effective pathway management.