Male Roach Research Articles

Breeding Tubercles, Papillomatosis and Dominance Behaviour of Male Roach (Rutilus rutilus) During the Spawning Period

AbstractWe studied the relationship between the breeding tubercle ornamentation (i.e. skin roughness) and male pre‐spawning dominance and courtship behaviour in roach (Rutilus rutilus) within an experimental laboratory system. Sexually mature fish were caught during their migration to their spawning pond and their behaviours were studied in an artificial spawning arena. Males behaved naturally both in terms of male–male interactions and attempts to achieve spawnings. Males having many, large breeding tubercles (i.e. rough skin) were significantly more often dominant in our dyadic trials than those with smooth skin. The dominant male in the trial exhibited a more active courtship behaviour than its subordinate rival. Papilloma skin disease did not affect the dominance rank. As a result of the relationship between skin roughness and male dominance, breeding tubercles may be used by the females as a cue for choosing a high‐quality mate in a roach lek. Thus, breeding tubercles might offer a workable tool for examination of sexual selection among cyprinids.

Parasitism, condition and number of front head breeding tubercles in roach (Rutilus rutilus L.)

Abstract – In a previous study on the male roach, Rutilus rutilus, we found a positive correlation between sexual ornamentation, breeding tubercles (BTs) on lateral sides and parasite resistance. As a continuation of that study, we examined another measure of sexual ornamentation – number of BTs on front head – of male roach from five populations. BTs on head correlated positively with fish size in two populations and with condition in one population, but not with parasite resistance (proportion of dead parasites) in any of the populations. Moreover, head BTs correlated negatively with the number of two parasite species (Rhipidocotyle campanula and Myxobolus mülleri) in two populations, but positively with the number of a third parasite (Raphidascarus acus) in one population. In addition, a negative correlation with spleen size was found in one population. The present results suggest that head BTs of male roach – although the patterns vary between populations – may signal condition and parasite load, but not resistance, in contrast to lateral BTs. Therefore, our results are in line with the hypothesis of multiple‐message sexual ornaments.

Epizootic cutaneous papillomatosis, cortisol and male ornamentation during and after breeding in the roach Rutilus rutilus

The prevalence of epidermal papillomatosis in roach is known to peak during the spawning period and to be higher in males than in females. The high occurrence of papillomatosis in polluted waters suggests that stress may contribute to the outbreak of the disease. However, little is known about breeding-induced stress in fish and its relationship with diseases. In this study, plasma cortisol concentration, hematocrit and the relative size of the spleen were determined in healthy and diseased male and female roach Rutilus rutilus during and shortly after spawning in a wild population. In addition, the sexual ornamentation (breeding tubercles on the lateral sides and on the frontal) of male roach during spawning was examined. Plasma cortisol concentration was higher during than after the spawning period, and higher in males than in females during spawning, indicating a spawning-induced stress and higher spawning stress among males. There was no correlation between cortisol concentration and the intensity of papillomatosis (number of scales under papilloma tumors) among the diseased fish. However, the significant interaction sex x disease status revealed by ANCOVA suggested that diseased males could be more prone to increased cortisol levels than diseased females or healthy males. Hematocrit values (ratio of the volume of red blood cells to total volume of blood) but not condition factor were lowered in papilloma-diseased fish after spawning. The relative size of the spleen was greater in males than in females. The number of frontal breeding tubercles correlated negatively with the intensity of papillomatosis. Experimental studies are needed to investigate the association of papillomatosis with stress and cortisol.

Exposure of juvenile roach (Rutilus rutilus) to treated sewage effluent induces dose-dependent and persistent disruption in gonadal duct development.

Wild roach (Rutilus rutilus) have been found with intersex gonads in rivers throughout the United Kingdom. The incidence of intersexuality is strongly correlated with discharges of estrogenic treated sewage effluent into those rivers, and this has led to the hypothesis that estrogenic chemicals in effluents are feminizing wild male fish. In this study, early-life stage roach (50 days post hatch, dph) were exposed for 150 days to a graded concentration (0%, 12.5%, 25%, 50%, and 100%) of treated sewage (primarily domestic) effluent to examine the effects of exposure on sexual differentiation and development. Measurement of steroid estrogens and alkylphenolic chemicals in the effluent and a resulting dose-dependent induction of vitellogenin (VTG; a female-specific, estrogen-dependent plasma protein) confirmed that the fish had been exposed and responded to "estrogen" in the effluent. Exposure to treated sewage effluent induced feminization of the reproductive ducts in "male" roach in a dose-dependent manner (in full-strength effluent, 100% of the fish had feminized ducts), indicating that the disruption of the gonad ducts seen in wild roach is the result of exposure to treated sewage effluents during early-life stages. There were no effects of treated sewage effluent exposure on germ cell development; therefore, no oocytes occurred in the testes of the feminized male roach. Subsequent, depuration of the effluent exposed fish in "clean" water for 150 days resulted in a reduction in plasma VTG but no alteration of the feminized ducts, indicating that the effect of the treated sewage effluent on reproductive duct development was permanent. The causality of oocytes in the testes of wild male roach therefore remains to be elucidated.

Effects of ECF-Bleached Kraft Mill Effluent on Reproductive Steroids and Liver MFO Activity in Populations of Perch and Roach

Samples of perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations were collected in Lake Saimaa in September-October, after the onset of vitellogenesis and deposition of yolk in the eggs. The study area received elemental chlorine-free (ECF)-bleached kraft mill effluent (BKME). The pulp and paper mill studied used chlorine dioxide for bleaching and its effluents were treated in a modern activated sludge plant. The amounts of chlorophenolics in the bile of perch and roach at the mill site, 1 km from the discharge point, were two to four times higher than in fish from the upstream reference site. In the roach population near the mill liver the 7-ethoxyresorufin 0-deethylase (EROD) activity was four times that measured in the reference areas. However, the EROD activity in the perch remained unchanged. The liver 7-pentoxyresorufin 0-dealkylase (PROD) activity was induced to twice the amount only in male roach near the mill, whereas the relative liver size (LSI) was increased in female and male roach and female perch. The plasma concentrations of oestradiol-17β were decreased in female perch and female roach, but increased in male roach at the mill site. Near the mill, vitellogenin gene expression was also reduced in female perch. In addition, the plasma testosterone concentrations were reduced in female and male perch near the mill. No differences were noted in the plasma immunoglobulin concentrations in roach and in the relative gonad size (GSI) in the perch and roach populations. The condition factor was significantly lower only in female roach near the mill.

Gender specific developmental transformation of a cockroach bifunctional muscle

AbstractAdult male and female cockroaches,Periplaneta americana, differ in their capacity for sustained flight. Tethered 20 day adult males flap their wings about 15 min; females 12 seconds. Males are less massive and have greater total wing area than do females, with wing loading only about half that of the female. The basalar muscle, a major wing depressor in flight, is also sexually dimorphic. In males it is 1.5× more massive and has a cross sectional area 1.2× greater than the female homologue. Muscle fibers of the adult male and female basalar muscles are ultrastructurally and biochemically distinct. Female fibers have a myofilament array similar to that of other non‐flight locomotory muscles, with 10–12 actin filaments surrounding each myosin filament. Adult male fibers typically have six actin filaments around each myosin filament. The male fibers also appear to be more oxidative. The volume density of mitochondria is about 3× greater and the specific activity for citrate synthase, an oxidative indicator, is 3.5× greater in male fibers than in female fibers. Male basalar muscle shows an enhanced ability to resist fatigue when its motoneurone is stimulated at flight frequency; homologues from the male terminal nymph and 20 day adult female are both highly fatiguable. The basalar muscle of both male and female terminal nymphs are similar in ultrastructural and biochemical profile and are not greatly different from the adult female. In male roaches there may be important neuronal or hormonal inputs at about the time of the terminal molt to adulthood that direct the transformation of the basalar muscle in time for the assumption of a new behavioral role—flight. © 1994 Wiley‐Liss, Inc.

Detailed information about parasites revealed by sexual ornamentation

One hypothesis assumes that sexual ornamentation has evolved to reveal an individual's health and vigour. Therefore, choosy mates may use ornamentation as an indicator of the presence and effectiveness of genes for resistance against parasites (Hamilton & Zuk (Science, Wash. 218, 384 (1982))). However, the connection between parasites and sexual ornamentation may be more direct: the different characters of the ornamentation could reveal the contribution of each sexual hormone to the whole hormone mix that induced the ornamentation. As androgens and oestrogens are known to weaken specifically parts of the immune system (Grossmann 1985), and several parasites require a specific aspect of the immune system to be countered effectively, the hormone mix may reveal the actual use of an animal's immune system which depends on the presence and burden of, or even susceptibility to, different parasites. Therefore detailed information about a host's parasites could be available by studying its sexual ornamentation. Breeding tubercles, the sexual ornamentation of many fish, are induced by several androgens and at least one oestrogen (Wiley & Colette 1970). I studied four characteristics of the ornamentation of male roach (Rutilus rutilus) and found that two of them could be used to discriminate between males that are infected with either Diplozoon or nematodes, the two most severe parasites found. Furthermore, the number of parasites of each group correlates negatively with the expression of one or both of the other ornamental characters. A female roach could potentially decode a male's ornamentation to gather a sort of clinical picture of him and use this information in her choice of mate.

Ontogeny of the invertebrate humoral immune response: Studies on various developmental stages of the American cockroach (Periplaneta americana)

Earlier studies revealed that a specific adaptive humoral immune response can be induced in the American cockroach ( Periplaneta americana ) to the soluble protein complex, Honeybee venom (HBT). We have undertaken a series of ontogenetic studies to determine if there are differences between the protective responses of roaches representing different developmental stages. Our results indicated that the response to HBT in the immature cockroach (nymphs weighing 200–500 mg) was characterized by a significant lag period before immune protection began to develop. However, by the second week of the response, reactivity was comparable to that of the adult. Old adult male roaches (animals 5 months into adulthood) displayed a significant decline in reactivity during the early phases of the response in comparison to younger adults, and in general, appeared to be less vigorous in generating protection. Both the nymph and old adult roaches demonstrated good secondary responsiveness. The results from these experiments indicated that the developmental stage of the roach could be directly correlated to the degree of immunocompetency possessed by the animal. This is similar to the ontogenetic sequence typically found for immune reactivity in vertebrates.

The Patterns of Enzymatic Compensations for Temperature in the Coxal Muscle of Periplaneta americana (Linn.)

Different patterns of compensation are exhibited by the maximal catalytic activities ($V_{max}$) of enzymes associated with energy metabolism in the coxal muscle of adult Periplaneta americana of the two sexes during acclimation to 16 and 32 C. The most common pattern is translation with rotation, exemplified by succinate dehydrogenase (SDH) in males and lactate dehydrogenase (LDH) in females. While aldolase activity of male roaches exhibits translational change, LDH activity in the same insects shows a complicated rotational alteration. The noncompensation has been detected for aldolase and SDH only of female insects. A sex-specific metabolic reorganization has been shown by the variation of the values of ratios of the activities of SDH to LDH and of SDH to aldolase due to thermal acclimation of cockroaches. The sexual dimorphism in the levels of enzymatic activities in the leg muscle of this insect has been found to depend on the thermal history of the animal and the temperature of assay of the ...

Control of a sex-limited haemolymph protein by corpora allata during ovarian development in Periplaneta americana (L.).

1. The removal of corpora allata from females of the roach, Periplaneta americana, soon after the imaginal molt prevented growth and yolk formation in the oocytes.2. No immediate effect on ovarian development was noticed when mature adult females were allatectomized.3. The haemolymph protein concentration of allatectomized females failed to reach the level of the sham-operated female roaches of the same age.4. Electrophoresis of haemolymph proteins on cellulose acetate strips revealed a gradual decrease and final disappearance of one of the main protein fractions in the allatectomized females.5. The haemolymph protein concentration of ovariectomized roaches rose to a level far in excess of that of sham-ovariectomized roaches of the same age. A significant increase in protein fraction 5 has been observed in the ovariectomized roaches compared with that of sham-ovariectomized roaches.6. In male roaches fraction 5 remained at low concentration at all times, suggesting that protein fraction 5 is sex-limited in character.7. Allatectomized roaches exhibited a slower rate of incorporation of tritiumlabelled amino acids into haemolymph proteins than the sham-operated roaches.8. It is concluded that the effects of corpora allata on egg maturation and yolk deposition may be due to their influence on metabolic processes, particularly the synthesis of a sex-limited haemolymph protein which presumably enters the growing oocytes.

ADENOSINETRIPHOSPHATASE ACTIVITY OF AMERICAN COCKROACH AND WOODROACH THORACIC MUSCLE

1. The adenosinetriphosphatase (ATPase) activity of the thoracic muscle of the American cockroach, Periplaneta americana, and the woodroach, Leucophaea maderae, was studied. The optimum conditions for eliciting maximum ATPase activity of the muscle of these two species are: 0.2 ml. of 0.01 M ATP, 0.05 ml. of 0.04 M CaCl2 2H2O, 0.15 ml. of 0.5 M diethylbarbiturate buffer of pH 7.4, and 0.05, 0.10 and 0.15 ml. of one per cent homogenate.2. The ATPase activity of the muscle from females was activated less by calcium than was that of the male American cockroach. The degree of calcium activation of the ATPase of the female woodroach muscle was intermediate between that of the male and female cockroach muscle.3. The ATPase activity of muscle from female American cockroaches 10 to 30 days of age was greater than that of male roaches of the same ages. Present results suggest that there is not a difference in the ATPase activity of muscle from male and female woodroaches.

The odorous attractant of the American cockroach, Periplaneta americana (L.). I. Quantitative aspects of the response to the attractant.

1. Procedures have been developed for studying quantitatively the response of the male American cockroach to the odorous attractant of the female. 2. The percentage of male roaches responding to extracts of the attractant of the female has been found to vary with the log of the concentration of the attractant throughout a wide range. 3. Adaptation to the olfactory stimulus has been demonstrated. 4. A theory of adaptation is offered.

The Differences Between Male and Female American Roaches in Total Lipid Content and in Susceptibility to DDT

The Differences Between Male and Female American Roaches in Total Lipid Content and in Susceptibility to DDT

EFFECTS OF pH AND OF VARIOUS CONCENTRATIONS OF SODIUM, POTASSIUM, AND CALCIUM CHLORIDE ON MUSCULAR ACTIVITY OF THE ISOLATED CROP OF PERIPLANETA AMERICANA (ORTHOPTERA)

1. Twenty-five solutions which contained KCl (0.0, 0.2, 0.4, 0.6, and 0.8 gm. per liter), in combination with CaCl(2) (0.0, 0.2, 0.4, 0.6, and 0.8 gm. per liter), 10.0 gm. of NaCl, and 0.2 gm. of NaHCO(3) per liter of solution were tested in order to determine satisfactory KCl/CaCl(2) ratios in an insect physiological salt mixture for the maintenance of muscular activity by the isolated crop of the American roach. Satisfactory activity products (0.390 to 0.549) were obtained in seven mixtures with KCl/CaCl(2) ratios of 0.2/0.2, 0.4/0.4, 0.6/0.6, 0.8/0.8, 0.2/0.4, 0.4/0.6, and 0.6/0.8, expressed as gram per liter. These ratios lie between 0.50 and 1.00. In solutions which contained calcium, but no potassium, approximately 50 per cent of the crops exhibited an initial tone increase and were arrested in rigor. See Fig. 2. In solutions which contained potassium, but no calcium, all crops showed an initial loss of tone and arrest in relaxation. See Fig. 2. 2. Seven KCl/CaCl(2) ratios (see paragraph 1 above) were tested with eight NaCl concentrations (1.0, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, and 1.8 per cent) at a pH of 8.0. In these mixtures, the ones with KCl/CaCl(2) ratios of less than 1.0 produced higher activity products than those with ratios equal to 1.00. The highest average activity product (0.849) was obtained in the solutions with 0.2 gm. of KCl and 0.4 gm. of CaCl(2) per liter. 3. Four KCl/CaCl(2) ratios (0.2/0.2, 0.4/0.4, 0.2/0.4, and 0.4/0.6 gm. per liter) were tested with 1.4, 1.5, and 1.6 per cent NaCl at a pH of 7.5. When analyzed with data from comparable solutions at a pH of 8.0, it was found that 1.4 per cent NaCl afforded an optimum environment for isolated crop activity. 4. Effects of hydrogen and hydroxyl ion concentrations were studied at pH values of 6.8, 7.5, 8.0, and 8.9. The highest average activity product, 1.011, was produced at a pH of about 8.0. 5. A satisfactory physiological salt solution for the isolated foregut of the American roach, Periplaneta americana, would contain 14.0 gm. of NaCl, 0.4 gm. of CaCl(2), 0.2 gm. of KCl, and 0.2 gm. of NaHCO(3) per liter of solution. This mixture should have a pH value between 7.8 and 8.2. 6. Durations of crop activity extending over periods as long as 25 hours were quite common, and several crops maintained contractions for more than 30 hours. The greatest longevity was for crop 814, from a female, which continued activity for slightly more than 47 hours. 7. A significant difference between the activity products of the crops from males and the crops from females was recorded. Although there was not a significant difference in the amount of food ingested by males and females, 12 hours after feeding there was more food in the females' crops, and the food progressed more rapidly through the males' crops than through the females'. In addition, crops from the two sexes reacted differently to the effects of day old solutions. This sex difference is apparently related to an inherently increased activity of the crop from the male roach.