Natural Breeding Habitats Research Articles

Physiology and fertility of two gull species in relation to plastic additives' exposure

Understanding the impact of plastic and its additives on wild species is crucial as their presence in the environment increases. Polybrominated diphenyl ethers (PBDEs), once used as flame retardants, were restricted due to known toxic effects, but are still detected in the environment. Naturally occurring methoxylated PBDEs (MeO-BDEs) can result from PBDE transformation and may cause similar hazardous effects. Yellow-legged gulls (Larus michahellis, YLG) and Audouin's gulls (Ichthyaetus audouinii, AG) are highly susceptible to plastic additives, due to their distribution, trophic position, and behaviour. In this study, we assessed PBDEs and MeO-BDEs uptake in different tissues and their effects on physiological and reproductive parameters. Findings indicate that, apart from annual differences, adult AG accumulated more MeO-BDEs than YLG in a natural breeding habitat (Deserta), while the latter had lower PBDE levels than YLG breeding in the city of Porto. In relation to chicks, only YLG from Deserta showed higher PBDE concentrations than AG chicks. Individual analysis of each physiological parameter revealed impacts only for adult YLG from Deserta, with neurofunction and immune system inhibition at higher MeO-BDE concentrations. For chicks, AG showed impaired neurofunction, while YLG chicks from Porto exhibited potential genotoxicity effects triggered by higher MeO-BDE levels. Overall health analysis showed activation of antioxidant defences and compromised immune system in YLG adults from Porto due to high values of PBDEs, while chicks from Deserta exhibited inflammation and oxidative stress with high concentrations of MeO-BDEs in the same species. Fertility parameters showed significant differences for sperm counts though suggesting individuals may be able to compensate any exposure effects. This study confirms the widespread presence of plastic-associated compounds and their harmful effects on gulls, particularly on neurofunction, immune system, oxidative balance and fertility, especially due to the presence of MeO-BDEs.

Assessment of fishing gear efficiency, species diversity, and socioeconomic impacts on fishermen along the Jamuna River, Bangladesh

The Jamuna River in Bangladesh is a vital source of freshwater aquatic resources and a natural breeding habitat for freshwater fish. However, recent declines in gear efficiency and species variety have significantly impacted the economic situation of fishermen. A study was conducted on 117 fishermen in Sariakandi upazilla, Bogra district, Bangladesh, from July 2022 to June 2023. The data was collected through direct visits, group discussions, and in-person interviews. The study identified 18 fishing gears and found that the seine net was the most effective gear for 8 months, with Cypriniformes being the most dominant fish order. The highest species abundance was recorded in September, while the lowest was in February. Only two types of fishing crafts were recorded during this period. The socioeconomic conditions of the fishermen were documented, with 71% being professionals and the rest being occasional. Most were over 40 years old, experienced, and had a large family. Their homes were kacha dwellings, with only 6% missing sanitary facilities and 76% using kacha latrines. Annual earnings ranged from 12500 to 169000 Tk, with 41% relying primarily on fishing and the remainder on other activities. A total of 59% of the fishermen borrowed loans from non-governmental organizations. This study shows that diminishing species diversity and total catch significantly impact fishermen's socioeconomic conditions. The government should take proper steps to protect the natural ecosystem of the Jamuna River and enhance the living needs of fishing communities in the study area.

Phytotelmata accounts for Aedes breeding places in Mantup Sub-district, Lamongan District, Indonesia

Abstract. Fauziyah S, Susanti SF, Hariyono H, Fazirrah V, Novitasari AE, Fadhilah N, Sucipto TH, Naw SW. 2023. Phytotelmata accounts for Aedes breeding places in Mantup Sub-district, Lamongan District, Indonesia. Biodiversitas 24: 4820-4828. Dengue infection still remains a public health problem in Indonesia, which is classified as a tropical country. Some environmental factors that contribute to the transmission of dengue infection are human migration, human activity, food supply, and climate change. The other type of breeding place is natural breeding habitats, called phytotelmata. This study aims to investigate the diversity of Aedes species in phytotelmata from Mantup Sub-district, Lamongan, East Java, Indonesia. The analytical observational study was conducted with a purposive sampling design. Mosquito larvae collection was carried out from February to March 2023 in Mantup Sub-district, an endemic region of dengue infection in Lamongan. Immature mosquitoes were reared in the laboratory till they merged into adult mosquitoes. This study found four groups of phytotelmata: leaf axils, bamboo joints, fallen leaves, and coconut shells. Leaf axils were the predominant type of phytotelmata (86.67%). Meanwhile, the lowest percentage was coconut shells and fallen leaves (3.33%). A total of 56 mosquito larvae consisting of 12 male Aedes aegypti, 21 female Ae. aegypti, 12 male Aedes albopictus, and 11 female Ae. albopictus were collected from 30 observation points. Eleven families of phytotelmata were found in this study. The predominant family was Araceae (33.3%), while the lowest were Agavaceae, Commelinaceae, Marantaceae, and Liliaceae (3.33%). Phytotelmata accounts for mosquito breeding places, which should be noticed and considered in dengue vector control programs.

Invertebrate abundance increases with vegetation productivity across natural and agricultural wader breeding habitats in Europe

Grassland breeding waders have been steadily declining across Europe. Recent studies indicating a dramatic decline in grassland invertebrates' abundance and biomass, the key food of most grassland wader chicks, suggest a likely driver of the demise of waders. While agricultural intensification is generally inferred as the main cause for arthropod decline there is surprisingly little information on the relationship between land use intensity and total arthropod abundance in grasslands. Here, we explored those relationships across several key wader breeding habitats by surveying ground-active, aerial and soil-dwelling invertebrate communities in five European countries that range from natural undisturbed bogs to intensively managed grasslands. Using maximum vegetation growth and soil moisture content we investigated how they shape the size of the invertebrate community within and across different countries. We found predominantly positive relationships between grassland invertebrate abundance, biomass and body weight with increasing vegetation growth and soil moisture. Maximum vegetation growth was strongly positively related to ground-active invertebrate abundance and biomass and abundance of soil dwelling invertebrates (mainly earthworms). Body weight of aerial invertebrates furthermore increased with increasing maximum vegetation growth. Our results provide little support for the hypothesis that agricultural practices associated with intensification of grassland management result in an abundance decline of invertebrate prey for wader chicks. Conservation practices aiming to enhance wader chick survival require a careful balancing act between maintaining habitat productivity to secure high prey abundance, and keeping productivity low enough to maintain open swards that do not need to be cut before chicks have fledged.

Predation of Aedes aegypti Eggs By Foraging Ants Solenopsis invicta, Myrmicaria brunnea, Diacamma rugosum, and Monomorium minimum.

The diseases transmitted by Aedes mosquitoes, such as dengue, chikungunya, yellow fever, and Zika, are ever-increasing. Rapid and unplanned urbanization adversely impacts various endemic species such as ants and facilitates the breeding of Aedes mosquitoes. We have observed the predatory potential of ants over Aedes eggs in urban breeding habitats, and their impact on Aedes mosquito breeding was determined by a field experiment that mimicked the natural breeding habitats. It was found that 99.4% of eggs were removed from the experimental containers by foraging ants in 4 days. The present study demonstrates the role of ants as a natural regulator, limiting Aedes mosquito breeding.

First natural breeding of the endangered dusky gopher frog (Lithobates sevosus) in captivity.

To date, all captive breeding of the dusky gopher frog, Lithobates sevosus, a federally listed endangered species, has been accomplished using in vitro fertilization (IVF). Here, we describe multievent and highly fecund captive reproduction of dusky gopher frogs driven solely by natural environmental factors. Six pairs of L. sevosus were kept in a 3.7 × 4.4 m2 outdoor enclosure designed to resemble their natural breeding habitat, which included a pool and three artificial burrows. Modifications to the enclosure that simulated temperatures and conditions within their natural range during winter were added in October and removed in late February. Following a warm, rainy period, five egg masses were laid between March 5 and 11, 2020. The number of oocytes per egg mass was 2300 ± 409 (range = 1341–3565), with the total across all five egg masses being 11,501. Of these oocytes, the hatching rate was 68.58 ± 10.05% (range = 37.53%–95.59%), with a total of 7887 successful hatchlings overall. Clutch sizes were similar to those in the wild and greater than those typically produced using IVF; thus, natural breeding can substantially increase the number of frogs available for reintroduction programs. Although assisted reproductive technologies such as IVF will continue to be useful for ensuring the success of strategic genetic pairings of captive L. sevosus, the new tool of nonassisted reproduction in specifically designed outdoor enclosures is an important advancement for the conservation and recovery of this endangered species.

Detection of Knockdown-Resistance Mutations (V1016G and F1534C) in Dengue Vector from Urban Park, Surabaya, Indonesia

An urban park is potentially a source of vector-borne disease transmission due to it being a natural and artificial mosquito breeding habitats combined with people's continuous presence. Thus, this study aims to screen the occurrence of knockdown-resistance (kdr) mutant alleles (V1016G and F1534C) in mosquito populations collected from urban parks in Surabaya, Indonesia. Cross sectional study was conducted in July 2019. A total of 28 ovitraps were installed in seven urban parks, having four ovitraps installed in each park. In total, 1,662 eggs were collected, and only 187 emerged into adult mosquitoes, consisting of 97 Aedes (Stegomyia) aegypti and 90 Aedes (Stegomyia) albopictus. All-female adult mosquitoes (n=55) were tested using allele-specific polymerase chain reaction assay (AS-PCR) to detect voltage gated sodium channel (VGSC) gene mutations. This study found no mutations in Valine to Glysine mutation in point 1016 (V1016G) and Phenylalanine to Cysteine in point 1534 (F1534C) alleles in both two species. All of mosquito samples have wild type genotype of kdr alleles (V1016V and F1534F). Data were analysed using R Studio 1.4 Version by Genetics package. Results showed that the frequency of resistant alleles (G1016 and C1534) was zero, and the frequency of susceptible allele was 1 (V1016 and F1534). Insecticide bioassay could not be established due to the limited number of adult mosquitoes, so insecticide resistance status could not be determined. However, this study can be used as preliminary monitoring for the vector control program.

Assessing the linkage of mosquito diversity with tree holes in Multan

Multan is a vast city expanding day by day by engulfing agricultural lands that leads to poor hygienic conditions. Such conditions help in proliferation of arthropod vectors and vector borne diseases including mosquito borne diseases. With the present scenario of climate change and anthropogenic activities, natural breeding habitats of mosquito species are being destroyed or lost resulting in shift of oviposition behavior from natural breeding sites to artificial ones. Tree holes are considered as one of preferred natural habitats for many species of mosquitoes. Some mosquito species may prefer particular tree species for egg laying while others may prefer some other tree species. Most controlling activities against mosquitoes involve artificial habitat destruction, while natural sites especially tree holes are overlooked due to lack of knowledge. Considering this scenario, the present study was planned to check population of mosquitoes in tree holes at various habitats in urban and rural areas of Multan. Trees having holes were selected on different urban and rural sites. A total 213 mature trees were visited on different selected sites and only 25 trees with holes were found. Data was collected on fortnightly basis; the collected specimens were brought to laboratory for identification purpose. Results of this study have shown that a total of 1008 mosquito larvae of three species; Aedes albopictus, Culex quinquefasciatus and Culex vagans, were collected from the tree holes. Highest population of mosquitoes collected from mango tree holes which covered 40% of total mosquito population. Species Aedes albopictus comprises 51% of total collected population with highest numbers while Culex vagans found in least numbers and covered 16% of total mosquito population.

Assessing the linkage of mosquito diversity with tree holes in Multan

Multan is a vast city expanding day by day by engulfing agricultural lands that leads to poor hygienic conditions. Such conditions help in proliferation of arthropod vectors and vector borne diseases including mosquito borne diseases. With the present scenario of climate change and anthropogenic activities, natural breeding habitats of mosquito species are being destroyed or lost resulting in shift of oviposition behavior from natural breeding sites to artificial ones. Tree holes are considered as one of preferred natural habitats for many species of mosquitoes. Some mosquito species may prefer particular tree species for egg laying while others may prefer some other tree species. Most controlling activities against mosquitoes involve artificial habitat destruction, while natural sites especially tree holes are overlooked due to lack of knowledge. Considering this scenario, the present study was planned to check population of mosquitoes in tree holes at various habitats in urban and rural areas of Multan. Trees having holes were selected on different urban and rural sites. A total 213 mature trees were visited on different selected sites and only 25 trees with holes were found. Data was collected on fortnightly basis; the collected specimens were brought to laboratory for identification purpose. Results of this study have shown that a total of 1008 mosquito larvae of three species; Aedes albopictus, Culex quinquefasciatus and Culex vagans, were collected from the tree holes. Highest population of mosquitoes collected from mango tree holes which covered 40% of total mosquito population. Species Aedes albopictus comprises 51% of total collected population with highest numbers while Culex vagans found in least numbers and covered 16% of total mosquito population.

Status of the invasive mosquito species Aedes aegypti (L., 1762) and Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) in Turkey

Aedes aegypti (L., 1762) and Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) are important vectors of arboviruses. In Turkey, Ae. albopictus eggs were detected in the Thrace area of northwestern Turkey for the first time in 2011. In 2015, studies revealed the spread of Ae. albopictus and the first detection of Ae. aegypti within northeastern Turkey was reported. This paper reports the results of a survey of the presence and distribution of Ae. albopictus and Ae. aegypti in Turkey conducted over 5 years. As of 2019, monitoring studies were conducted on the presence of Ae. albopictus and Ae. aegypti in five geographical regions (Black Sea, Central Anatolia, Marmara, Mediterranean and Aegean Regions). A comprehensive range of potential larval habitats, such as tires, artificial containers, cemeteries, water bottles and natural breeding habitats, were assessed. In addition, standard ovitraps and adults’ traps were used in some localities. This study showed that Ae. albopictus , in particular, expanded its distribution each year and has the potential to extend its range throughout Turkey over the next few years. In Turkey, the distribution of Ae. aegypti is currently limited to northeastern Turkey. Future work focused on determining more effective surveillance and control studies is discussed.

Genetic differentiation over a small spatial scale in the smooth newt (Lissotriton vulgaris)

Understanding the distribution of genetic variation is central for both population biology and conservation genetics. Genetic population structure can be primarily affected by the species’ dispersal ability, which is assumed to be limited in many amphibians. In this study, we estimated allelic differentiation metrics and FST indices to investigate genetic variation among natural breeding ponds of smooth newts (Lissotriton vulgaris) over a small spatial scale. Based on six microsatellite loci, we found a small, but significant allelic differentiation among clusters of natural breeding ponds (i.e. ‘local regions’), which result was in line with the calculation of corresponding hierarchical FST values. Analysis of molecular variance also indicated significant between-region variation in the study area. Pairwise estimations showed that only the furthermost regions differed from each other in both differentiation measures, but this difference was not attributable to geographic distances between ponds. Our results provide evidence that hierarchical genetic structure can be characteristic to breeding ponds of smooth newts on a small spatial scale in their natural breeding habitat, but dispersal distance may be less limited than previously thought in these philopatric caudates.

Impact of land cover and landfills on the breeding effect and nest occupancy of the white stork in Poland

Food wastes are among the factors with the greatest effects on animal populations. The white stork is among bird species that clearly profit from feeding at landfills, at least in Western Europe and North Africa. However, the rate and the consequences of this feeding are still unknown in the Central-Eastern European population, which differs from the western population not only in terms of migration routes but also in the greater availability of suitable natural breeding habitats due to less intensified agriculture. The aim of the study was to describe the use of landfills and its consequences in terms of probability of nest occupation and breeding effects in different regions of Poland. Although the most important factors influencing nest-site selection and breeding effect are still habitat quality and weather conditions, distance to landfills is important in selection of nest sites. White storks use landfills most intensively late in the breeding season, independently of the density of breeding pairs. The results suggest that the use of landfills is not currently essential in the Central-Eastern European population of the white stork, does not affect breeding effect, and may be more frequent in non-breeders. However, this phenomenon is still developing and requires continuous monitoring.

People behavior and anopheles mosquitous bionomic and its correlation with malaria parasite prevalence and case fatality rate (CFR) in West Seram Regency

WHO mentions that 300-500 million of people in the world are infected with malaria every year, 110 million of people perform the symptoms, and 2.7 million are even died. In 2005, malaria patients in West Seram Regency were 7.760 people. The research design was Survey and Case control in order to investigate the behavior of local society, Anopheles mosquito bionomic, malaria prevalence and case fatality rate (CFR). Purposive sampling was taken from the people of 2 villages in 3 districts with the highest numbers of patients. 30 people were taken from each village so total sample was 180 respondents. Anopheles bionomics involved habitat and breeding. Malaria cases in 2012-2016 obtained from public health center, health department office and public hospitals. Data analysis was done by using Pearson correlation test. The results showed that people behavior strongly agreed in overcoming the spread of Anopheles mosquitoes and malaria. Natural breeding habitat in swamps area where mangrove trees grow and sago trees at trenches, rice fields, ponds and water on the boat. Anopheles larvae species encountered was Anopheles sundaicus that actively bite all night inside and outside the house with peak activity at 02.00-03.00 a.m. Average larval density was 5.00, 9.00 and Average density of Anopheles mosquitoes was 5.09 - 9.85. The Prevalence Rate of Malaria is still high and Case Fatality Rate (CFR) is low. There is a significant correlation between people behavior and prevalence rate and no correlation with Case Fatality Rate (CFR)

Leach’s Storm PetrelsHydrobates leucorhousbreeding on Gloup Holm: the third discovered breeding site in Shetland

In the UK, Leach’s Storm Petrel Hydrobates leucorhous breeding colonies are few and geographically very remote. Single Leach’s Storm Petrels were heard calling from burrows on Gloup Holm, north Shetland, in July 2019, July 2020 and August 2020, in response to call-playback. The occupied burrow network found in August 2020 was examined by endoscope and a Leach’s Storm Petrel eggshell was seen, constituting the first proven breeding record at this site. A sample call was recorded from each bird heard, sonograms produced, and comparison with criteria for determining sex from calls indicated the bird heard in 2019 was female and those in 2020 were one or possibly two males. Currently, Leach’s Storm Petrel breeds in very low numbers in Shetland on just two small islands. Restoration projects to eradicate introduced predators and preserve natural breeding habitat on select other islands could result in increased breeding numbers.

Larvae of the blow fly Caiusa testacea (Diptera: Calliphoridae) as egg predators of Polypedates cruciger Blyth, 1852 (Amphibia: Anura: Rhacophoridae)

We investigated the impact of dipteran predators on eggs in foam nests of the Common Hour-glass Tree Frog Polypedates cruciger Blyth, 1852 (Anura: Rhacophoridae) in central Sri Lanka. Foam nests (n=24) of P. cruciger were examined at their natural breeding habitats and infected (n=8) and uninfected spawns (n=16) were identified. Emerging tadpoles were collected in a water container hung under each spawn and the average number of tadpoles (N) hatched from infected spawns (N=0) was compared with that of uninfected spawns (N=354 ± 67). Three severely infected spawns were brought to the laboratory and the fly larvae were reared until they metamorphosed to adults. Morphological and molecular identification of the flies confirmed them as belonging to Caiusa testacea Senior-White, 1923 of the family Calliphoridae. The infected spawns were completely destroyed and an estimated average of 400 P. cruciger eggs per spawn were lost. The results revealed a high impact of Caiusa testacea on egg and embryo mortality of P. cruciger.

Mapping the Geographical Distribution and Seasonal Variation of Dengue and Chikungunya Vector Mosquitoes (<i>Aedes aegypti and Aedes albopictus</i>) in the Epidemic Hotspot Regions of India: A Step towards the Vector Control and Sustainable Health

Aedes aegypti and Aedes albopictus are known vector mosquitoes for several emerging arthropod-borne viruses (arboviruses) including dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses across the world. Aedes species vector mosquitoes are blamed for the spread of dengue and chikungunya in India. Dengue and Chikungunya is the illustrious public health problems in the country, dengue has public health importance and cumulative burden to the affected community, especially in the Southern States of India, since 1991, and followed by the highest outbreaks of chikungunya in the Southern India, 2006. Dengue cases reported from 24 States and 3 Union Territories out of 34 States / Union Territories in India, and highest reports recorded in 5 major States (Tamil Nadu, Kerala, Karnataka, Punjab and West Bengal), during 2017. All the four serotypes of dengue virus (DEN-1, DEN-2, DEN-3, and DEN-4) are detected across the country various with space and time. Mapping the geographical distribution and seasonal variation of dengue and chikungunya vector mosquitoes (Aedes aegypti and Aedes albopictus) is absolutely significant for the systematic surveillance, organization, and implementation, accordingly, the public health authority possibly will make prevention measures to control the dengue epidemic earlier in advance and monitoring the endemic situation in the state as well as in the country, continuously [16,17,18]. Aedes aegypti and Aedes albopictus vector mosquito’s density caused by the man-made containers (socio-economic variables), and the natural breeding habitats, and land use / land cover types, environmental risk factors, and climate determinants. All the four serotypes of dengue virus (DEN-1, DEN-2, DEN-3, and DEN-4) are reported in India. The study has mainly focused on the major endemic districts in India, where the state of endemic has accumulative problems, and is grumbling the community. Aedes aegypti and Aedes albopictus are the known vector mosquitoes of dengue and chikungunya. The endemic districts have unique landscape terrain and land use / land cover pattern, and climate factors (precipitation, temperature, relative humidity, and saturation deficiency). The major landscape terrain has hilly, plain and coastal areas. The epidemic areas receive rainfall by both the southwest monsoon and the northeast monsoon from April to November (almost 8 months), and has the average temperature range of 22°C to 31°C, and relative humidity of 70 % to 90 %, and the present study contains the vector density is highly influenced by the maximum number of rainy days, and the occurrences of dengue epidemics clustered regions in India mainly where it receives annual mean rainfall ranging from 300 mm to 1200 mm. The spatial distribution and seasonal variation of vector mosquitoes (Aedes aegypti and Aedes albopictus) in the identified endemic districts are absolutely griping the situation by seasonal variation in precipitation and temperature, land cover spatial variations, socio-economic, and ecological differences have directly affected the profusion of vector mosquitoes and the incubation period of the dengue and chikungunya virus, and thus, huge epidemics in the identified endemic districts along with entire state. Consequently, the nature and manmade environment is fuelling for the huge number of profusion of Aedes species mosquitoes in the epidemics area. Mapping the spatial distribution and seasonal variation of Aedes aegypti and Aedes albopictus, using Remote Sensing, and GIS technology could be an ultimate tool for functioning a dengue surveillance in the endemic districts as well as in the country, and thus, comfort to the public health experts to organize, implement and choose an appropriate control strategy for the prevention measures to control the grumpy situation in the dengue endemic hot spot regions in the country.

Physicochemical Characters of Mosquitoes Natural Breeding Habitats: First Record in High Dengue Hemorrhagic Fever Cases Area, East Java, Indonesia

This research aims to identify physicochemical characteristics in natural breeding habitats/ phytotelmata of dengue vector—including Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus. The research was conducted during rainy season and pre-dry season (from January to June 2017) in the region with the high cases of Dengue Hemorrhagic Fever (DHF). The entomological survey was carried out by stratified random sampling in urban and rural areas in order to find potential breeding habitats, every natural breeding habitats in sampling location were checked for the presence of Aedes larvae. Physicochemical characters that consist of temperature, turbidity, carbon dioxide, ammonia, nitrate, sulphate, pH and dissolved oxygen were recorded. Larval species were taken and then identifying activities were conducted in the Laboratory of Entomology. Data were analysed using the Chi-square test. Results showed that only dissolved oxygen that significantly associated with larval abundance (p=0.039). while others are not significantly associated. Whereas, other characters are associated with each other, carbon dioxide associated with the ammonia and sulphate (p=0.001; p=0.028). Turbidity associated with the dissolved oxygen (p=0.022) and pH associated with nitrate (p=0.001).

Long-term changes of breeding success in Montagu’s Harrier Circus pygargus

Over a period of almost twenty years, clutch size and breeding success in the Montagu’s Harrier were investigated in the context of changing environmental conditions in the species’ natural breeding habitats in eastern Poland. During the study periods (1990-95 and 2003-12) a decline was noted in the number of breeding pairs in the population nesting on the calcareous peat bogs near Chełm, not far from the Polish-Ukrainian border. Statistically significant differences in breeding parameters between the two periods were also observed. In the first period clutch volumes were greater, as the dimensions of the individual eggs were larger; additionally, more eggs hatched and the hatchling survival rate was higher. Some habitat conditions were different in the two periods, with the water level and height of vegetation near the nests being lower in the second period. The harriers’ food in the two study periods fluctuated strongly with regard to the content of small mammals and compensatory items. In the second period a distinct increase in predator pressure was noted. Pressure from terrestrial predators diminished whereas that from aerial predators increased. Broods in semi-colonies, where birds actively defended their nests, enjoyed a higher rate of survival, as did nests situated far in from the edge of peat bogs. The results suggest that the decline in breeding numbers was driven by increased predation, which was in turn a consequence of habitat changes in the natural environment of eastern Poland.

Offshore oil rigs – a breeding refuge for Norwegian Black-legged Kittiwakes Rissa tridactyla?

In recent decades, the population of Black-legged Kittiwake Rissa tridactyla has declined substantially in most parts of the North Atlantic. Concurrently, there has been an increased urbanisation of the species, with Kittiwakes colonising nearshore buildings and other man-made structures. Here we document the prevalence and performance of Kittiwakes breeding on offshore oil rigs on the Norwegian shelf and compare their reproductive output with parallel data from the nearest Kittiwake colonies monitored on the Norwegian coast. At least six (10%) of the 63 rigs addressed in the study were reported to have breeding Kittiwakes, four of which had a total of 1,164 breeding pairs in 2019. One of these offshore colonies was situated in the Barents Sea, the other five in the Norwegian Sea. Overall the Kittiwakes breeding on oil rigs had a moderate to high productivity, ranging on average between 0.61–1.07 large chicks per nest. This was higher than the productivity in most (but not all) colonies on man-made structures on the coast in the same period, and much higher than that in natural breeding habitats. The differences in Kittiwake productivity between offshore and coastal habitats are likely related to parallel differences in food availability and exposure to predators, but this warrants further study. Besides helping us explore key drivers of Kittiwake productivity, the increasing numbers of Kittiwakes breeding on man-made structures both offshore and on the coast clearly provide a significant contribution of juveniles to the impoverished Kittiwake population in Norwegian waters.

Predator–prey interactions and the cannibalism of larvae of Armigeres subalbatus (Diptera: Culicidae)

Predation and cannibalism can affect the co-existence of mosquito species or the assemblage of mosquito species (i.e., community structure). In this study, predatory feeding patterns and cannibalism of larvae of Armigeres subalbatus mosquitoes were quantified under laboratory conditions using Aedes albopictus and Culex uniformis larvae as prey organisms. Rate of consumption of prey larvae and the rate of cannibalism of 1st to 4th instar larvae of Armigeres subalbatus were reported at 24 h intervals with and without alternative food supplement. Both the 3rd and 4th instar larvae of Ar. subalbatus showed a substantial predation on the larvae of Ae. albopictus (33.6 ± 4.4) and Cx uniformis (47.3 ± 7.6). The cannibalism of the predatory larvae was strongly correlated to the larval density (r = 0.9). The predator and the prey density and the given food type were significant factors that determined the rate of pupation, death and the emergence as adults. A significant relationship was shown for the co-occurrence of predatory larvae and the prey larvae at the 85 natural breeding habitats observed at the field (χ2 = 74.4, p < 0.001). Nine breeding sites (10.6%) were positive for both prey and predatory larvae. Our study showed robust information about the predatory and cannibalistic behavior of Ar. subalbatus larvae emphasizing their role in managing the population structure of mosquito communities.