Wetland butterfly thriving in abandoned jungle: Neptis rivularis in the Czech Republic.

With ongoing insect declines, species expanding in distribution and abundance deserve attention, as understanding their success may help design conservation strategies for less successful species. Common causes of these successes include warmer climates, novel resources, and exploiting land use change, including land abandonment. These factors affect the nymphalid butterfly Neptis rivularis, developing on Spiraea spp. shrubs and reaching the north-western limits of its trans-Palearctic distribution in Central Europe. We combined mark-recapture, behaviour analysis, and distribution modelling to study N. rivularis in wetlands of the Trebonsko Protected Landscape (IUCN category V). The long-living adults (up to 4 weeks) spent a considerable amount of time searching for partners, ovipositing and nectaring at Spiraea shrubs, alternating this with stays in tree crowns, where they located cool shelters, spent nights, and presumably fed on honeydew. They formed high-density populations (310 adults/ha), exploiting high host plant abundance. They adhered to floodplains and to conditions of relatively mild winters. The ongoing Spiraea encroachment of abandoned alluvial grasslands is, thus, a transient situation, ultimately followed by forest encroachment. Rewilding the habitats by introducing native ungulates presents an opportunity to restore the disturbance regime of the sites. The increased resource supply combined with a warming climate has opened up temperate Europe to colonization by N. rivularis.

Rewilding by large ungulates contributes to organic carbon storage in soils.

The concept of rewilding, which focuses on managing ecosystem functions through self-regulation by restoring trophic interactions through introduced animal species with little human intervention, has gained increasing attention as a proactive and efficient approach to restoring ecosystems quickly and on a large scale. However, the science of rewilding has been criticized for being largely theory-based rather than evidence-based, with available data being geographically biased towards the Netherlands and Scandinavian countries, and a lack of objective data on rewilding effects on soil processes and C sequestration. In response to a call for data-driven experimental rewilding projects focused on national contexts, we collected unique data on the effects of large herbivore rewilding on soil properties from eight sites in the Czech Republic. These include sites with a wide range of edaphic characteristics that were grazed by Exmoor ponies, European bison, and back-bred Bos primigenius cattle (singly or in combination) for 2-6 years on areas ranging from ≈30 to ≈250 ha. Despite the relatively short duration of rewilding actions and considerable variability in the response rate of soil properties to grazing, our results indicate improved nutrient availability (evidenced by higher nitrification rate or higher soluble nitrogen concentration) and accelerated ecosystem metabolism (higher soil microbial biomass and dissolved carbon content). On longer-grazed pastures, rewilding contributed to soil carbon sequestration associated with increased water holding capacity and improved soil structure. However, other soil properties (reduced dissolved P concentration or total P content) showed signs of low P availability in the soils of the rewilding sites. Therefore, carcass retention should be considered where possible. Our data, although limited in number and geographic coverage, allow us to conclude that large ungulate rewilding has the potential to enhance soil carbon sequestration and related ecosystem services in rewilding areas. At the same time, we urge similar monitoring as an essential part of other rewilding projects, which will ultimately allow much more robust conclusions about the effects of this management on soils.

Geography of Indian Butterflies: Patterns Revealed by Checklists of Federal States.

Butterflies are widely used to analyze biogeographical patterns, both at the global and regional scales. Thus far, most of the latter originated from well-surveyed northern regions, while the species-rich tropical areas lag due to a lack of appropriate data. We used checklists of 1379 butterfly species recorded in 36 federal states of the Republic of India (1) to explore the basic macroecological rules, and (2) to relate species richness and the distribution of endemics and geographic elements to geography, climate, land covers and socioeconomic conditions of the states. The area, land covers diversity and latitude did not affect species richness, whereas topographic diversity and the precipitation/temperature ratio (energy availability) were positive predictors. This is due the geographic and climatic idiosyncrasies of the Indian subcontinent, with its highest species richness in the small, densely forested mountainous northeast that receives summer monsoons. The peninsular effect that decreases the richness towards the tip of subcontinent is counterbalanced by the mountainous forested Western Ghats. Afrotropical elements are associated with savannahs, while Palearctic elements are associated with treeless habitats. The bulk of Indian butterfly richness, and the highest conservation priorities, overlap with global biodiversity hotspots, but the mountainous states of the Western Himalayas and the savannah states of peninsular India host distinctive faunas.

Perishing rich, expanding poor: Demography and population genetic patterns in two congeneric butterflies.

In human-altered landscapes, specialist butterflies typically form spatially restricted populations, genetically differentiated due to dispersal restrictions. Generalists, in contrast, display minimum differentiation but high genetic diversity. While local-level actions suffice to conserve specialists and landscape-level actions are necessary for generalists, minimum information exists regarding conservation of species with intermediate features. We targeted two congeneric butterflies, the recently re-expanding Argynnis adippe and the strongly declining A. niobe, co-occurring in the pastoral landscape of the Carpathian Mountains, Czech Republic. We integrated species distribution models, mark-recapture and microsatellite analysis to compare their habitat requirements, adult demography, dispersal and genetic patterns, and expanded the genetic analysis across the Carpathian Arc and beyond to delimit spatial conservation units. In two mountain valleys, both species formed interconnected populations numbering thousands of individuals. Mobility patterns suggested the populations' interconnection across the Czech Carpathians. Genetic diversity was extremely poor in the nonthreatened A. adippe and moderate in the declining A. niobe. No population differentiation was detected within the Czech Carpathians (~1500 km2 ). Low genetic diversity and no differentiation was preserved in A. adippe across East Central Europe, whereas in A. niobe, populations from Serbia were differentiated from the Carpathian Arc + Alps. The high adult mobility linked to low differentiation probably reflects the distribution of larval resources, historically widespread but sparse and currently declining for A. niobe (grazing-disturbed grounds), while currently increasing for A. adippe (abandonment scrub, disturbed woodlands). Units as large as entire mountain systems define population boundaries, and hence conservation management units, for both species.

Exploring Cold Hardiness within a Butterfly Clade: Supercooling Ability and Polyol Profiles in European Satyrinae.

The cold hardiness of overwintering stages affects the distribution of temperate and cold-zone insects. Studies on Erebia, a species-rich cold-zone butterfly genus, detected unexpected diversity of cold hardiness traits. We expanded our investigation to eight Satyrinae species of seven genera. We assessed Autumn and Winter supercooling points (SCPs) and concentrations of putatively cryoprotective sugars and polyols via gas chromatography-mass spectrometry. Aphantopus hyperantus and Hipparchia semele survived freezing of body fluids; Coenonympha arcania, C. gardetta, and Melanargia galathea died prior to freezing; Maniola jurtina, Chazara briseis, and Minois dryas displayed a mixed response. SCP varied from -22 to -9 °C among species. Total sugar and polyol concentrations (TSPC) varied sixfold (2 to 12 µg × mg-1) and eightfold including the Erebia spp. results. SCP and TSPC did not correlate. Alpine Erebia spp. contained high trehalose, threitol, and erythritol; C. briseis and C. gardetta contained high ribitol and trehalose; lowland species contained high saccharose, maltose, fructose, and sorbitol. SCP, TSPC, and glycerol concentrations were affected by phylogeny. Species of mountains or steppes tend to be freeze-avoidant, overwinter as young larvae, and contain high concentrations of trehalose, while those of mesic environments tend to be freeze-tolerant, overwinter as later instars, and rely on compounds such as maltose, saccharose, and fructose.

Low winter precipitation, but not warm autumns and springs, threatens mountain butterflies in middle-high mountains.

Low-elevation mountains represent unique model systems to study species endangered by climate warming, such as subalpine and alpine species of butterflies. We aimed to test the effect of climate variables experienced by Erebia butterflies during their development on adult abundances and phenology, targeting the key climate factors determining the population dynamics of mountain insects. We analysed data from a long-term monitoring of adults of two subalpine and alpine butterfly species, Erebia epiphron and E. sudetica (Nymphalidae: Satyrinae) in the Jeseník Mts and Krkonose Mts (Czech Republic). Our data revealed consistent patterns in their responses to climatic conditions. Lower precipitation (i.e., less snow cover) experienced by overwintering larvae decreases subsequent adult abundances. Conversely, warmer autumns and warmer and drier springs during the active larval phase increase adult abundances and lead to earlier onset and extended duration of the flight season. The population trends of these mountain butterflies are stable or even increasing. On the background of generally increasing temperatures within the mountain ranges, population stability indicates dynamic equilibrium of positive and detrimental consequences of climate warming among different life history stages. These contradictory effects warn against simplistic predictions of climate change consequences on mountain species based only on predicted increases in average temperature. Microclimate variability may facilitate the survival of mountain insect populations, however the availability of suitable habitats will strongly depend on the management of mountain grasslands.

Restoring a butterfly hot spot by large ungulates refaunation: the case of the Milovice military training range, Czech Republic.

BACKGROUND: Refaunation/rewilding by large ungulates represents a cost-efficient approach to managing natural biotopes and may be particularly useful for areas whose biodiversity depends on disturbance dynamics and is imperilled by successional changes. To study impacts of refaunation on invertebrates, we focused on butterflies inhabiting the former military training range Milovice, Czech Republic, refaunated since 2015 by a combination of Exmoor pony ("wild" horse), Tauros cattle ("aurochs"), and European wisent. METHODS: We analysed butterfly presence-absence patterns immediately after the military use termination (early 1990s), prior to the refaunation (2009), and after it (2016-19); and current abundance data gained by monitoring butterflies at refaunated and neglected plots. We used correspondence analysis for the presence-absence comparison and canonical correspondence analysis for the current monitoring, and related results of both ordination methods to the life history and climatic traits, and conservation-related attributes, of recorded butterflies. RESULTS: Following the termination of military use, several poorly mobile species inclining towards oceanic climates were lost. Newly gained are mobile species preferring warmer continental conditions. The refaunated plots hosted higher butterfly species richness and abundances. Larger-bodied butterflies developing on coarse grasses and shrubs inclined towards neglected plots, whereas refaunated plots supported smaller species developing on small forbs. CONCLUSION: The changes in species composition following the cessation of military use were attributable to successional change, coupled with changes in species pool operating at larger scales. By blocking succession, large ungulates support butterflies depending on competitively poor plants. Restoring large ungulates populations represents a great hope for conserving specialised insects, provided that settings of the projects, and locally adapted ungulate densities, do not deplete resources for species with often contrasting requirements.

Succession of Dung-Inhabiting Beetles and Flies Reflects the Succession of Dung-Emitted Volatile Compounds.

Chemical cues, such as volatile organic compounds (VOCs), are often essential for insects to locate food. Relative to the volume of studies on the role of VOCs in insect-plant relationships, the role of VOCs emitted by dung and carrion in mediating the behavior of insect decomposers is understudied. Such relationships may provide a mechanistic understanding of the temporal axis of community assembly processes in decomposing insect communities. We focused on the temporal succession of volatiles released by cow dung pats and the potential influence on dung-inhabiting insects. Using gas chromatography/mass spectrometry we identified and quantified VOCs released from dung 1-h, and 1, 2 3, 5, and 7 d-old. We then related changes in VOCs to successional patterns of dung-inhabiting beetles and flies. We detected 54 VOCs which could be assigned to two successional groups, with chemical turnover in dung changing around day 2. The early successional group consisted primarily of aliphatic alcohols and phenols, and the late one of aliphatic esters, nitrogen- and sulfur-bearing compounds. Flies were predominately associated with the early successional group, mainly with 1-butanol. Beetles were associated predominately with the late-successional group, mainly with dimethyl trisulfide. This association between insect and chemical successional patterns supports the idea that habitat filtering drives the community assembly of dung-inhabiting insects on an aging resource. Moreover, the affinity of both insect groups to specific VOC groups provides a mechanistic explanation for the predictability of successional patterns found in dung-inhabiting insect communities.

Radical pruning of distribution data may result in loss of knowledge (Response to Larsen & Shirey).

Larsen & Shirey (2020) criticised our analysis of latitudinal changes in butterfly phenology on the grounds of improper data management. We admit some imprecisions, but show that stringent reanalyses did not change the overall results. We also show that unreasonable treatment of data may result in critical information loss.

Wolbachia affects mitochondrial population structure in two systems of closely related Palaearctic blue butterflies.

The bacterium Wolbachia infects many insect species and spreads by diverse vertical and horizontal means. As co-inherited organisms, these bacteria often cause problems in mitochondrial phylogeny inference. The phylogenetic relationships of many closely related Palaearctic blue butterflies (Lepidoptera: Lycaenidae: Polyommatinae) are ambiguous. We considered the patterns of Wolbachia infection and mitochondrial diversity in two systems: Aricia agestis/Aricia artaxerxes and the Pseudophilotes baton species complex. We sampled butterflies across their distribution ranges and sequenced one butterfly mitochondrial gene and two Wolbachia genes. Both butterfly systems had uninfected and infected populations, and harboured several Wolbachia strains. Wolbachia was highly prevalent in A. artaxerxes and the host's mitochondrial structure was shallow, in contrast to A. agestis. Similar bacterial alleles infected both Aricia species from nearby sites, pointing to a possible horizontal transfer. Mitochondrial history of the P. baton species complex mirrored its Wolbachia infection and not the taxonomical division. Pseudophilotes baton and P. vicrama formed a hybrid zone in Europe. Wolbachia could obscure mitochondrial history, but knowledge on the infection helps us to understand the observed patterns. Testing for Wolbachia should be routine in mitochondrial DNA studies.

Phenology responses of temperate butterflies to latitude depend on ecological traits.

Global change influences species' seasonal occurrence, or phenology. In cold-adapted insects, the activity is expected to start earlier with a warming climate, but contradictory evidence exists, and the reactions may be linked to species-specific traits. Using data from the GBIF database, we selected 105 single-brooded Holarctic butterflies inhabiting broad latitudinal ranges. We regressed patterns of an adult flight against latitudes of the records, controlling for altitude and year effects. Species with delayed flight periods towards the high latitudes, or stable flight periods across latitudes, prevailed over those that advanced their flight towards the high latitudes. The responses corresponded with the species' seasonality (flight of early season species was delayed and flight of summer species was advanced at high latitudes) and oceanic vs. continental climatic niches (delays in oceanic, stability in continental species). Future restructuring of butterfly seasonal patterns in high latitudes will reflect climatic niches, and hence the evolutionary history of participating species.

Temporal Segregation between Dung-Inhabiting Beetle and Fly Species.

The coexistence of ecologically similar species (i.e. species utilizing the same resource) is a major topic in ecology. Communities are assembled either through the biotic interactions of ecologically similar species, e.g. competition, or by the abiotic separation of species along gradients of environmental conditions. Here, we investigated the temporal segregation, succession and seasonality of dung-inhabiting Coleoptera and Diptera that utilize an identical resource in exactly the same way. The data were collected from two temperate pastures, one in the United Kingdom and the second in the Czech Republic. There was no evident temporal separation between ecologically similar coleopterous or dipterous taxa during succession. In contrast, these two orders were almost perfectly separated seasonally in both combined and site-specific datasets. Flies were most abundant in the summer, and beetles were more abundant in the spring and autumn. Ecologically similar beetles and flies also displayed seasonal separation in both combined and site-specific data. Analyses within site-specific data sets revealed such a separation at both the order and species level. Season is therefore the main temporal axis separating ecologically similar species of dung-inhabiting insects in temperate habitats, while succession aggregates species that may have similar environmental tolerances (to e.g. dung moisture). This separation between ecologically similar taxa of beetles and flies may be attributable to either competition-based niche separation or to temperature tolerance-based habitat filtering, since flies have peak activity in warmer months while beetles have peak activity in cooler months.

Life History Traits Reflect Changes in Mediterranean Butterfly Communities Due to Forest Encroachment.

The biodiversity of the Southern Balkans, part of the Mediterranean global biodiversity hot-spot, is threatened by land use intensification and abandonment, the latter causing forest encroachment of formerly open habitats. We investigated the impact of forest encroachment on butterfly species richness, community species composition and the representation of life history traits by repeated seasonal visits of 150 one-hectare sites in five separate regions in three countries-Greece, Bulgaria, and the Republic of Macedonia (FYROM-the Former Yugoslav Republic of Macedonia)- 10 replicates for each habitat type of grasslands, open formations and scrub forest within each region. Grasslands and open formations sites hosted in average more species and more red-listed species than scrub forest, while no pattern was found for numbers of Mediterranean species. As shown by ordination analyses, each of the three habitat types hosted distinct butterfly communities, with Mediterranean species inclining either towards grasslands or open formations. Analysing the representation of life history traits revealed that successional development from grasslands and open formations towards scrub forest shifts the community composition towards species overwintering in earlier stages, having fewer generations per year, and inhabiting large European or Eurosiberian (e.g. northern) ranges; it decreases the representation of Mediterranean endemics. The loss of grasslands and semi-open formations due to forest encroachment thus threatens exactly the species that should be the focus of conservation attention in the Mediterranean region, and innovative conservation actions to prevent ongoing forest encroachment are badly needed.

Three in One--Multiple Faunal Elements within an Endangered European Butterfly Species.

Ice ages within Europe forced many species to retreat to refugia, of which three major biogeographic basic types can be distinguished: "Mediterranean", "Continental" and "Alpine / Arctic" species. However, this classification often fails to explain the complex phylogeography of European species with a wide range of latitudinal and altitudinal distribution. Hence, we tested for the possibility that all three mentioned faunal elements are represented within one species. Our data was obtained by scoring 1,307 Euphydryas aurinia individuals (46 European locations) for 17 allozyme loci, and sequencing a subset of 492 individuals (21 sites) for a 626 base pairs COI fragment. Genetic diversity indices, F statistics, hierarchical analyses of molecular variance, individual-based clustering, and networks were used to explore the phylogeographic patterns. The COI fragment represented 18 haplotypes showing a strong geographic structure. All but one allozyme loci analysed were polymorphic with a mean FST of 0.20, supporting a pronounced among population structure. Interpretation of both genetic marker systems, using several analytical tools, calls for the recognition of twelve genetic groups. These analyses consistently distinguished different groups in Iberia (2), Italy, Provence, Alps (3), Slovenia, Carpathian Basin, the lowlands of West and Central Europe as well as Estonia, often with considerable additional substructures. The genetic data strongly support the hypothesis that E. aurinia survived the last glaciation in Mediterranean, extra-Mediterranean and perialpine refugia. It is thus a rare example of a model organism that combines attributes of faunal elements from all three of these sources. The observed differences between allozymes and mtDNA most likely result from recent introgression of mtDNA into nuclear allozyme groups. Our results indicate discrepancies with the morphologically-based subspecies models, underlining the need to revise the current taxonomy.

Thermoregulation and microhabitat use in mountain butterflies of the genus Erebia: importance of fine-scale habitat heterogeneity.

Mountain butterflies have evolved efficient thermoregulation strategies enabling their survival in marginal conditions with short flight season and unstable weather. Understanding the importance of their behavioural thermoregulation by habitat use can provide novel information for predicting the fate of alpine Lepidoptera and other insects under ongoing climate change. We studied the link between microhabitat use and thermoregulation in adults of seven species of a butterfly genus Erebia co-occurring in the Austrian Alps. We captured individuals in the field and measured their body temperature in relation to microhabitat and air temperature. We asked whether closely related species regulate their body temperature differently, and if so, what is the effect of behaviour, species traits and individual traits on body to air and body to microhabitat temperature differences. Co-occurring species differed in mean body temperature. These differences were driven by active microhabitat selection by individuals and also by species-specific habitat preferences. Species inhabiting grasslands and rocks utilised warmer microclimates to maintain higher body temperature than woodland species. Under low air temperatures, species of rocky habitats heated up more effectively than species of grasslands and woodlands which allowed them to stay active in colder weather. Species morphology and individual traits play rather minor roles in the thermoregulatory differences; although large species and young individuals maintained higher body temperature. We conclude that diverse microhabitat conditions at small spatial scales probably contribute to sympatric occurrence of closely related species with different thermal demands and that preserving heterogeneous conditions in alpine landscapes might mitigate detrimental consequences of predicted climate change.

Why do some women prefer submissive men? Hierarchically disparate couples reach higher reproductive success in European urban humans.

OBJECTIVES: Equality between partners is considering a feature of the functional partnerships in westernized societies. However, the evolutionary consequences of how in-pair hierarchy influences reproduction are less known. Attraction of some high-ranking women towards low-ranking men represents a puzzle. METHODS: Young urban adults (120 men, 171 women) filled out a questionnaire focused on their sexual preference for higher or lower ranking partners, their future in-pair hierarchy, and hierarchy between their parents. RESULTS: Human pairs with a hierarchic disparity between partners conceive more offspring than pairs of equally-ranking individuals, who, in turn, conceive more offspring than pairs of two dominating partners. Importantly, the higher reproductive success of hierarchically disparate pairs holds, regardless of which sex, male or female, is the dominant one. In addition, the subjects preferring hierarchy disparity in partnerships were with greater probability sexually aroused by such disparity, suggesting that both the partnership preference and the triggers of sexual arousal may reflect a mating strategy. CONCLUSION: These results challenge the frequently held belief in within-pair equality as a trademark of functional partnerships. It rather appears that existence of some disparity improves within-pair cohesion, facilitating both cooperation between partners and improving the pairs' ability to face societal challenges. The parallel existence of submissivity-dominance hierarchies within human sexes allows for the parallel existence of alternative reproductive strategies, and may form a background for the diversity of mating systems observed in human societies. Arousal of overemphasized dominance/submissiveness may explain sadomasochistic sex, still little understood from the evolutionary psychology point of view.

Conservation potential of abandoned military areas matches that of established reserves: plants and butterflies in the Czech Republic.

Military training generates frequent and irregular disturbance followed by succession, resulting in fine-scaled mosaics of ecological conditions in military training areas (MTAs). The awareness that MTAs may represent important biodiversity sanctuaries is increasing recently. Concurrently, changes in military doctrine are leading to abandonment of many MTAs, which are being brought under civilian administration and opened for development. We surveyed vascular plants in 43 and butterflies in 41 MTAs in the Czech Republic and compared the records with plants and butterfly records from 301 and 125 nature reserves, respectively. After controlling for effects of area, geography, and climate, we found that plant species richness was equal in the two land use categories; butterfly richness was higher in MTAs; reserves hosted more endangered plants and more endangered butterflies. Ordination analyses, again controlled for potential nuisance effects, showed that MTAs and reserves differed also in species composition. While specialist species of nationally rarest habitat types inclined towards the reserves, MTAs hosted a high representation of endangered species depending on either disturbed ground, or successionaly transient conditions. These patterns reflect the history of the national nature reserves network, and the disturbance-succession dynamics within MTAs. The conservation value of formerly army-used lands is increasingly threatened by abandonment, and conservationists should support either alternative uses mimicking army activities, or sustainable management regimes.

Reverse altitudinal cline in cold hardiness among Erebia butterflies.

There is strong evidence for a shifting of range boundaries by many temperate butterfly species to higher altitudes and latitudes. Climate change represents a potential threat to mountain fauna. Nevertheless, information on ecophysiological limits of individual species is scarce. We studied the lower thermal limits of four species representing the prevailingly mountain Holarctic butterfly genus Erebia. We measured the cold tolerance of hibernating larvae, namely the supercooling point (SCP) and the lower lethal temperature (LLT). Three mountain species were freeze avoiding, with various levels of SCP (-8 to -22 degree C), and LLT close to SCP. The only exception was lowland E. medusa, whose caterpillars were freeze tolerant with LLT (-21 degree C) slightly below its SCP (-17 degree C). Surprisingly, LLT was highest in the alpine E. tyndarus and lowest in E. medusa inhabiting lower altitudes with higher mean winter temperatures. We explain the observed reversed altitudinal cline in cold hardiness by the buffering function of snow cover in the hibernacula of caterpillars that is strong at high mountains but irregular, unpredictable and thus unreliable in lowlands.

Sexual arousal by higher- and lower-ranking partner: manifestation of a mating strategy?

BACKGROUND: High hierarchical status is associated with increased reproduction success in mammals. However the subordinate males are not totally eliminated from reproduction due to mate choice and alternative male strategies. Thus; the sexual arousal by higher-ranking or lower-ranking partner in humans may represent a proximate mechanism for realizing a reproductive strategy. AIM: To evaluate possible connection between mating strategy and sexual arousal by lower-ranking and higher-ranking partner. MATERIALS AND METHODS: Markers of possible reproductive success (the number and gender of relatives and self-reported attractiveness) were evaluated by questionnaire-based study on students (110 men and 195 women, aged 19 to 29, mean age 22.5 +/- 2.10SD). MAIN OUTCOME MEASURE: The correlation between markers of reproductive success and the sexual arousal by lower- and higher-ranking partner. RESULTS: Arousal by lower-ranking partner correlated positively with proportion of males in relatives (Spearman's r, males: 0.219*; females: 0.161*) and with self-reported attractiveness (males: r = 0.223*); arousal by higher-ranking partner correlated positively with self-attractiveness (females: r = 0.191*). DISCUSSION: We found markers of reproductive success despite of reduced number of offspring in nowadays population. CONCLUSION: The sexual arousal by lower- and/or higher-ranking partner appears to be a manifestation of a successful reproductive strategy, e.g. behavior connected to natural human behavior. Moreover, the sexual arousal by overemphasized hierarchy (e.g. dominant-slave play) considered to be a part of sadomasochistic sex (or so called BDSM) may represent an over emphasised manifestation of this reproductive strategy. *P < 0.05.

The significance of facultative scavenging in generalist predator nutrition: detecting decayed prey in the guts of predators using PCR.

Gut-content analyses using molecular techniques are an effective approach to quantifying predator-prey interactions. Predation is often assumed but scavenging is an equally likely route by which animal DNA enters the gut of a predator/scavenger. We used PCR (polymerase chain reaction) to detect scavenged material in predator gut homogenates. The rates at which DNA in decaying slugs (Mollusca: Pulmonata) and aphids (Homoptera: Aphididae) became undetectable were estimated. The detectability of DNA from both carrion types in the guts of the generalist predator Pterostichus melanarius (Coleoptera: Carabidae) was then determined. The effects of carrion age and weight, as well as beetle sex, on detection periods, were quantified. Laboratory trials measured prey preference of beetles between live and decaying prey. Further experiments measured, for the first time, feeding by P. melanarius on dead slugs and aphids directly in the field. In both field and laboratory, P. melanarius preferentially fed on dead prey if available, but preference changed as the prey became increasingly decayed. Disappearance rates for slug carrion in wheat fields and grasslands were estimated and P. melanarius was identified as the main scavenger. Comparison of the retention time for dead slugs in the field, with the detection period for decaying slug material in the guts of the predators, showed that PCR-based techniques are not able to distinguish between predated and scavenged food items. This could potentially lead to overestimation of the impact of predation on slugs (and other prey) by carabids. Possible implications of facultative scavenging by invertebrate predators for biocontrol and food-web research are discussed.