According to hunting statistics in the last two decades, both the population numbers and harvesting of roe deer in Poland have been on the increase from 597000 to 876000 animals and from 158000 to 172000 harvested individuals, respectively. The number of roe deer reported by hunters are mainly based on guesswork, therefore the objective of the study was to verify the inventory of roe deer conducted by hunting clubs in the Myślibórz Forest District (north-western Poland) and to determine the sex ratio and age structure this species. The study area is including 86 small size forest complexes and covers 12990 ha. Roe deer number were determined over four years from 2002 to 2006. In sampling plots (February 2002) data from snow tracking and driving census showed significant correlation (r = 0.663, p = 0.003) between the relative population density (N/km) – independent variable and population density (N/1000 ha) – dependent variable. Roe deer snow tracks were counted during five days each year on 16 line transects (length 66.4 km) and the relative population densities (animal per km*day–1) for the whole study area were calculated. These indices were inserted into the regression formula that was obtained from sampling plots. It allowed to calculate the population density (N/1000 ha) and then roe deer numbers inhabiting the study area. Population density ranged from 300.1-319.0 individuals/1000 hectares of forest, and the differences between the four years of study were statistically insignificant. In summer, the sex ratio of the population was 1:1.4 in favour of females, and the autumn increment of young animals amounted to 70.2 fawns/100 does. The average population number of roe deer assessed for these four years was 3568 individuals and was more than two times higher than the average population size (n = 1670) given by hunters.
Reproductive traits are among the most important biological characteristics that facilitate or impede the establishment of non-native fish into new environments. In several tributaries of the Lower River Danube (Bulgaria), the round goby (Neogobius melanostomus Pallas, 1814) is a recent invader. Specimens from the edge of the invasion front were collected monthly (March 2017 to May 2018) from each river. The pioneer individuals displayed relatively small body sizes. First maturation of females occurs at 49 mm total length. Based on the dynamics of oocyte size and GSI, it was established that spawning begins in early spring, at a relatively low water temperature (6-7 °C). The breeding season extended from March to June. Average absolute fecundity was 162 ± 62 oocytes, while average relative fecundity was 94 oocytes/g ± 24. Female fecundity is linearly dependent on the length and weight. Both of the known male alternative reproductive tactics were observed. Body condition factor was lowest during April for both sexes. The relationship between reproductive traits and invasive potential in N. melanostomus is discussed.
The reproductive biology of the marbled goby, Pomatoschistus marmoratus (Risso, 1810), was studied in the Strymon River estuarine system (northern Greece) between September 1997 and August 1999. Samplings were conducted on a monthly basis at the mouth of the river using a bag seine net and overall a total of 4 563 individuals were collected. The total length of males ranged between 2.5 and 6.0 cm and that of females between 2.8 and 5.7 cm, while that of unsexed individuals ranged between 1.2 and 2.9 cm. Sex ratio was 1.54:1 in favour of the females and statistically different from unity. The spawning of the species was extended, occurring between February and May. Mean absolute fecundity (F) was 1 386 (SE=8) oocytes and showed a significant positive exponential relationship with total length (F=14.387TL2.92), and total weight (F=1351TW0.83) of the fish. The relative fecundity ranged between 878 and 3 444 oocytes/g of total weight. Mean size at first maturity was estimated at 3.82 cm for the females and 4.66 cm for the males.
In birds of prey, food availability affects the entire breeding process, including reproductive success. Sequential polyandry, sometimes documented in raptors and owls, has been observed occasionally in Tengmalm’s owl in years of high food availability. In this study, the effect of food supply on the reproductive strategy of the central european Tengmalm’s owl population has been investigated. The availability of the main prey of owls was significantly below average in the study year 2014. This resulted in low breeding density of owls, delayed egg laying, small clutch sizes, and low reproductive success. Nevertheless, successful sequential polyandry of one Tengmalm’s owl female was recorded during the breeding season. The polyandrous female laid four eggs in each nests, and 50 % and 75 % of four hatched nestlings left the nest during the first and second breeding, respectively. In both nesting attempts, the two-year old female was of a substandard body mass and she abandoned the fledglings before they left the nests. Prey delivered by males to both nests was comprised mainly of alternative prey (birds and shrews). The results of this study suggest that there are probably some other factors, in addition to food availability, that may play a role in Tengmalm’s owl’s decisions in matters of parental care.
The adult sex ratio among the genus Parnassius is usually strongly male biased and close to 2 : 1. This paper presents the results of comparative studies, on the basis of data from wild and captive reared populations of apollo butterfly in the Pieniny National Park (Western Carpathians, Poland). Sex ratio among the wild population is strongly male biased and close to 2 : 1, whereas there was no sex ratio bias among the captive population. However, among the captive individuals caught after releasing into the wild, males significantly outnumbered females. There was a significant, sex-related, difference in activity pattern recorded in the field studies: while the majority of females were observed sitting, males were usually flying. This result suggests that the observed sex ratio shifting is at least partially an artifact caused by the more cryptic behaviour of females. The sex ratio bias was more pronounced in the wild population than in captive individuals caught after releasing into wild, which suggests that difference in detectability between the sexes is not the only reason for males outnumbering females.
We examined the influence of offspring mortality caused by hyperparasitism on the secondary sex ratio of Lysiphlebus hirticornis Mackauer, a solitary endoparasitoid of the aphid Metopeurum fuscoviride Stroyan, in the field. Females of L. hirticornis produce pseudo-gregarious broods, which may comprise more than 200 offspring. Hyperparasitoids [mainly Syrphophagus aphidivorus (Mayr)] attacked and killed up to 60% of the primary parasitoids inside mummified aphids, especially late in the season. Hyperparasitized broods were larger than hyperparasitoid-free broods, which suggests that the risk of hyperparasitism increased with mummy density. We tested the hypothesis that mortality caused by hyperparasitism is greater for female than male offspring of L. hirticornis. If mummy quality scales with mummy size, hyperparasitoids should choose the relatively larger over the relatively smaller mummies. In the absence of hyperparasitism, broods of L. hirticornis included approximately two daughters for each son; the sex ratio did not vary with brood size. In hyperparasitized broods, the sex ratio was nearly even. This result indicates that relatively more female offspring (developing in the larger mummies) than male offspring (developing in the smaller mummies) were killed by hyperparasitoids. We propose that sex-differential offspring mortality in L. hirticornis is the result of differences in optimal host choice between the primary parasitoid and the hyperparasitoids.
Helminths often occupy defined niches in the gut of their definitive hosts. In the dioecious acanthocephalans, adult males and females usually have similar gut distributions, but sexual site segregation has been reported in at least some species. We studied the intestinal distribution of the acanthocephalan Echinorhynchus borealis von Linstow, 1901 (syn. of E. cinctulus Porta, 1905) in its definitive host, burbot (Lota lota Linnaeus). Over 80% of female worms were found in the pyloric caeca, whereas the majority of males were in the anterior two-thirds of the intestine. This difference was relatively consistent between individual fish hosts. Worms from different parts of the gut did not differ in length, so site segregation was not obviously related to worm growth or age. We found proportionally more males in the caeca when a larger fraction of the females were found there, suggesting mating opportunities influence gut distribution. However, this result relied on a single parasite infrapopulation and is thus tentative. We discuss how mating strategies and/or sexual differences in life history might explain why males and females occupy different parts of the burbot gut., Arto Tuomainen, E. Tellervo Valtonen, Daniel P. Benesh., and Obsahuje bibliografii
Maternal effects of heat shock are reported for some species of insects, but little is known about such effects in the western flower thrips (WFT) Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). WFT is a pest of vegetables in greenhouses worldwide. It is susceptible to high temperatures in its natural environment and is controlled using heat treatment in China. WFT population growth is suppressed by a brief exposure to a high temperature of 40°C or 45°C in the laboratory. To explore the mechanism by which high temperatures suppress the growth of WFT populations, as well as the effects of multiple heat treatments on WFT, we recorded the duration of development and survival of immature WFT, and the sex ratio (female/male) and fecundity of F1, F2, F3 and F4 adult females that developed after a single heat shock, and those of F2 offspring after a double heat shock. We also recorded the longevity and ovarian structure of adult females of the treated generation (P) and their F1, F2 and F3 offspring after a single heat shock. In addition, we determined whether the effects of a heat shock on second instar nymphs and adults differed. The results indicate that exposure of the parental generation to 41°C or 45°C for 2 h significantly prolonged the duration of development, reduced survival of immature WFT and altered the sex ratio (female/male), longevity and fertility of their adult female offspring. The effects of a heat shock of 41°C persisted for two generations, whilst the effect of heat shock of 45°C persisted for three generations. In addition, double heat shocks had more pronounced effects than a single heat shock. Heat shock administered to second instar nymphs resulted in a decrease in the number of ovarioles, whilst a heat shock administered to adults resulted in ovariole deformity. The maternal effects of heat shock in terms of the biological parameters of WFT, structure and number of ovarioles, are critical in determining the suppression of the growth at high temperatures of WFT populations.
The acanthocephalan Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 differs from most other species in the genus Echinorhynchus Zoega in Müller, 1776 by infecting mysids (order Mysida) instead of amphipods (order Amphipoda) as intermediate hosts. Here we report on the occurrence of E. bothniensis in mysids (Mysis segerstralei Audzijonytė et Väinölä) and in its fish definitive hosts in a high Arctic lake. Out of 15 907 sampled mysids, 4.8% were infected with a mean intensity of 1.05 worms (range 1-5), although there was notable variation between samples taken in different years and sites. Larger mysids appear more likely to be infected. Of five fish species sampled, charr,Salvelinus alpinus (Linnaeus), and a benthic-feeding whitefish morph, Coregonus lavaretus (Linnaeus), were the most heavily infected (mean abundances of 80 and 15, respectively). The adult parasite population in fish exhibited a female-biased sex ratio (1.78 : 1). Although E. bothniensis is rather unique in infecting mysids, many aspects of its natural history mirror that of other acanthocephalan species., Raija-Liisa Aura, Daniel P. Benesh, Risto Palomäki, E. Tellervo Valtonen., and Obsahuje bibliografii
a1_This study describes the parasitoid species complex associated with seven closely related species of sexual (Siederia rupicollella, S. listerella, Dahlica lazuri, D. charlottae and D. lichenella) and parthenogenetic (Dahlica fennicella and D. triquetrella) Naryciinae (Lepidoptera: Psychidae) in Central Finland. A thorough ecological analysis of all the species of parasitoids recorded was combined with analyses of molecular data. Mitochondrial and nuclear DNA data were obtained from all the species in order to (1) detect cryptic species associated with host specialization, (2) assign undescribed males to females, and (3) verify the morphological identification of closely related species. A DNA barcoding technique was employed to identify host species from parasitized larval remains. By sampling more than 10,000 host larvae, of which 25.7% were parasitized, nine parasitoid species were identified morphologically, including both koinobionts (Ichneumonidae: Diadegma incompletum, Macrus parvulus, Trachyarus borealis, T. solyanikovi, T. fuscipes, T. brevipennis and Braconidae: Meteorus affinis) and idiobionts (Ichneumonidae: Orthizema flavicorne, Gelis fuscicornis). Ecological characteristics such as time and mode of host attack, time of emergence and level of specialization differed widely. The results show that differences in parasitoid biology need to be taken into account when studying differences in percentage parasitism of sexual and parthenogenetic Naryciinae. The molecular data revealed that one parasitoid species M. parvulus may consist of two cryptic forms associated with the sexual and parthenogenetic hosts, respectively. The data further establishes that T. brevipennis and some T. fuscipes are in fact morphotypes of one species. The large variation in mitochondrial DNA within species and its inconsistency with nuclear DNA demonstrate that current species and genus delimitation is inadequate in the, a2_Trachyarus species group. Our study shows that it is essential to use DNA barcoding methods when investigating host-parasitoid complexes., and Jelmer A. Elzinga, Kees Zwakhals, Johanna Mappes, Alessandro Grapputo.