Ecology of Laridae under conditions of unstable hydrological regime: colony sizes and synchronization of reproduction

The problem of criteria for distinguishing colonies from similar socio-demographic structures (mainly in terms of nesting density) is highly relevant and has remained in the focus of attention of ornithologists for a long time. The synchronization of reproduction in a colony is one of the criteria which require special development. Based on particular works (1972–2005), I present synchronization of the reproduction of gulls in colonies of different sizes. In contrast to previous studies, this paper uses a specially developed Index of Synchronization of Bird Breeding (Isr) to study this phenomenon, making it relatively easy to determine its level. The index distinguishes between different species of birds of this group: 75.7% (white-winged black tern) and 97.6% (black-headed gull) of the total variability of synchronization of breeding birds in colonies. Frequent failure of nesting attempts often causes repeated (compensatory) reproduction, which in the case of a mass manifestation significantly reduces the synchronization of the nesting period in colonies and thus significantly reduces this indicator. It is proved that a higher synchronization of reproduction characterizes small colonies (up to 50 nests). In all species of gulls, the beginning of reproduction in different colonies differs in terms of the appearance of the first eggs by 1–10 days and at the beginning of mass egg-laying – by 1–18 days. To the same extent, they differ in the timing of the hatching of eggs. In small colonies, the total egg-laying period is shorter by 34.9–49.7% compared to larger colonies. My observations show that large colonies are formed by the nesting of several small colonies on one plot. This phenomenon is noticeable during periods of mass re-nesting of birds after a high loss of nests (up to 69.5% or more) because of severe flooding. Differences in the breeding periods of colonies that differ in size appear when several small colonies with different breeding periods of birds are combined into one larger colony. This phenomenon is well detected in the formation of several sub-colonies and in the differences in the timing of reproduction of different parts of a large colony.

Phenotypic Switching of Staphylococcus aureus Mu50 Into a Large Colony Variant Enhances Heritable Resistance Against β-Lactam Antibiotics

Phenotypic heterogeneity within a bacterial population may confer new functionality and allow microorganisms to adapt to fluctuating environments. Previous work has suggested that Staphylococcus aureus could form small colony variants to avoid elimination by therapeutic antibiotics and host immunity systems. Here we show that a reversible non-pigment large colony morphology (Mu50∆lcpA-LC) was observed in S. aureus Mu50 after knocking out lcpA, coding for the LytR-CpsA-Psr family A protein. Mu50∆lcpA-LC increased resistance to β-lactam antibiotics, in addition, the enlarged cell size, enhanced spreading ability on solid medium, and reduced biofilm formation, suggesting better abilities for bacterial expansion. Moreover, the expression of spa encoding protein A was significantly increased in Mu50∆lcpA-LC. This study shows that besides the small colony variants, S. aureus could fight against antibiotics and host immunity through phenotype switching into a large colony variant.

Coyote (Canis latrans) predation of colonial rodents facilitated by Golden Eagles (Aquila chrysaetos)

Interactions between Coyote (Canis latrans) and Golden Eagle (Aquila chrysaetos) are complex and likely not yet fully documented or understood. I observed a Coyote prey on a Black-tailed Prairie Dog (Cynomys ludovicianus) at the edge of a large colony in Grasslands National Park, Saskatchewan. The prairie dogs were vigilant toward three Golden Eagles circling above, and the Coyote apparently used this to its advantage. As such, the eagles appeared to facilitate the ability of the Coyote to rush in virtually undetected and prey on a prairie dog that was distracted by the avian predators. This observation is of scientific interest because it is another example of the varied interactions between Coyotes and Golden Eagles, which is competitive and includes kleptoparasitism.

The speckled ground squirrel (Spermophilus suslicus) in Belarus: new localities, old threats, and prospects of conservation

The study was carried out as part of the project "Superrodent" and is devoted to the description of new record localities of the spotted ground squirrel (Spermophilus suslicus s. l.) discovered by the authors during 2019–2020. It is one of the rarest species of rodents and mammals in the fauna of Belarus in general. This species suffers from anthropogenic changes in the environment and its agricultural development and to ensure its protection it is listed in a number of ‘red lists’, including the IUCN Red List and the Red Book of the Republic of Belarus (since 2015). The search for ground squirrel habitats was carried out in two stages. The first included the analysis of the literature on already known localities and biotope preferences, including cartographic data to identify promising areas to search for. The second stage provides a direct survey of prospective sites, their photo documentation and a detailed description. In total, nine new habitats of the species were identified within four administrative districts of Minsk Oblast of Belarus: Nesvizh Raion (4), Stowbtsy Raion (1), Baranivka Raion (1) and Kapyl Raion (2). In addition, an inspection of the sites previously identified by the authors revealed that some of them have already disappeared or are in critical state, the reason for which is primarily the land ploughing. In fact, today there are only six viable suslik settlements in Belarus. All of them are confined to elevated areas of the Kopyl ridge, which is located in the northern part of the Continental biogeographic region. Most of the surviving colonies are not large and consist of a few dozen to 150 living burrows. The number of the only large colony (Yushevichi) is estimated at 10 to 11 thousand individuals. All other inhabited colonies are located at a distance as far as 6 km from the Yushevichi colony. In other regions of Belarus, despite searches, ground squirrels are currently not found. The key threats to the species' existence are the ploughing of colonies and the overgrowth of tall grasses and trees and shrubs. In our opinion, for the long-term preservation of the species in the country, it is necessary to establish an appropriate protection regime (management), as well as the implementation of comprehensive monitoring: monitoring of threats, successions of plant communities, and the state of ground squirrel populations. Suggestions for protection and further monitoring of locations are given. Among other initiatives, the authors sent proposals to local authorities on granting protection status to areas with settlements of ground squirrels.

Состояние колоний морских птиц полуострова Старицкого (Тауйская губа, Охотское море)

Comparison of the 2019 census results with those obtained earlier permits to evaluate changes in the number and distribution of nesting seabird colonies оn the Staritsky Peninsula over the past 10 years. The Staritsky Peninsula coasts and the Gertner and Veselaya bay islands are located in close proximity to the city of Magadan, and therefore are subject to maximum anthropogenic pressure. The total number of breeding seabirds (including the urban population of the Slaty-backed Gull in the city of Magadan) increased from 36 thousand individuals in 2009 to 57.6 thousand individuals in 2019. Simultaneously, the proportion of main species changed in the largest colonies around the city - on the Tri Brata Islands and Cape Ostrovnoy. A very large colony (3,230 birds) of the Pelagic Cormorants near the mouth of the Dukcha River, which appeared in the last 20 years, now became the largest in the Tauy Bay. The colony formation and growth was promoted by the urban wastewaters discharged into the Gertner Bay.

Growth, death, and resource competition in sessile organisms

Population-level scaling in ecological systems arises from individual growth and death with competitive constraints. We build on a minimal dynamical model of metabolic growth where the tension between individual growth and mortality determines population size distribution. We then separately include resource competition based on shared capture area. By varying rates of growth, death, and competitive attrition, we connect regular and random spatial patterns across sessile organisms from forests to ants, termites, and fairy circles. Then, we consider transient temporal dynamics in the context of asymmetric competition, such as canopy shading or large colony dominance, whose effects primarily weaken the smaller of two competitors. When such competition couples slow timescales of growth to fast competitive death, it generates population shocks and demographic oscillations similar to those observed in forest data. Our minimal quantitative theory unifies spatiotemporal patterns across sessile organisms through local competition mediated by the laws of metabolic growth, which in turn, are the result of long-term evolutionary dynamics.

Solenopsis invicta (red imported fire ant).

S. invicta is an ant native to South America. It is an aggressive generalist forager that occurs in high densities and can thus dominate most potential food sources. It breeds and spreads rapidly and, if disturbed, can relocate quickly, ensuring the survival of the colony. S. invicta is highly invasive because of its high reproductive capacity, large colony size, ability to exploit human disturbances, wide food range and ability to sting. Its stinging ability allows it to subdue prey and even repel larger vertebrate competitors from resources (ISSG, 2014). S. invicta has become widespread in the southern USA and Caribbean after its introduction in the 1930s (Morrison et al., 2004). It has also been introduced to parts of Australia and New Zealand. S. invicta is one of the most notorious invasive ants and has been nominated for the 100 World's Worst Invaders list compiled by the Invasive Species Specialist Group (ISSG, 2014).

Intraspecific differences in the invasion success of the Argentine ant Linepithema humile Mayr are associated with diet breadth

The Argentine ant, Linepithema humile Mayr, has spread to almost all continents. In each introduced region, L. humile often forms a single large colony (supercolony), the members of which share the haplotype “LH1”, despite the presence of other supercolonies with different genetic structures. However, the mechanisms underlying the successful invasion of LH1 ants are unclear. Here, we examined whether diet breadth differs between more successful (LH1) and less successful (LH2, LH3, LH4) L. humile supercolonies in Japan to better understand the processes responsible for invasion success. The standard ellipse areas (SEAs) of δ13C and δ15N and their ranges (CR and NR) were used as diet breadth indices. The SEAs of LH1 were much larger than those of the less successful supercolonies despite no differences in the baseline SEAs of arthropods within the supercolony habitats, indicating that the invasion success of a supercolony is associated with its diet breadth. Furthermore, LH1 had a broader CR than the other supercolonies, suggesting that which might be derived from superior resource exploitation ability. Our study highlights the importance of focusing on intraspecific differences in diet breadth among supercolonies when assessing organisms that can potentially invade and become dominant in new habitats.

FIRST REPORT ON HUNTING BEHAVIOR OF MIGRATORY ORIENTAL HONEY-BUZZARD (PERNIS PTILORHYNCHUS ORIENTALIS) TOWARDS MIGRATORY GIANT HONEYBEE (APIS DORSATA DORSATA) (HYMENOPTERA: APIDAE) ON JAVA ISLAND, INDONESIA

Both Migratory Oriental Honey-buzzard (Pernis ptilorhynchus orientalis) and migratory giant honeybee (Apis dorsata dorsata) can be found in South-east Asia. The Oriental Honey-buzzard is the main predator of the giant honeybee, prey upon its honeycomb, larvae, and honey. Its existence always follows the migration of the giant honeybee. They stay on Java island during the migratory season. The giant honeybee lives in a large colony and has a powerful sting that is useful for defence against its predators. The bee is among the most dangerous animals since its threatening defensive behavior causes severe impact on the eagle and is even frequently fatal for human beings. Data collections on hunting behavior of the Oriental Honey-buzzard were based on irregular observations and interviews between the year 2003 to 2019. We categorized five hunting behaviors during data collections: flying orientation around the bee’s nest, attack on living nest, failure to collect the living nest, preying upon the newly empty nest, and transferring attack of the angry bee to people nearby. The safest hunting for the Oriental Honey-buzzard is to prey upon newly empty nest left by the honeybee. When the nest was still occupied by the bee colonies, the eagle should develop a strategy to avoid and reduce the risk of being attacked. It sometimes transfers the attack to people nearby.

Short Communication: Antibacterial potential of Actinomycetes isolated from mangrove sediment in Tanjung Api-Api, South Sumatra, Indonesia

Rozirwan, Muda HI, Ulqodry TZ. 2020. Short Communication: Antibacterial potential of Actinomycetes isolated from mangrove sediment in Tanjung Api-Api, South Sumatra, Indonesia. Biodiversitas 21: 5723-5728. Actinomycetes play an important role in the decomposition process of organic matter in mangrove sediments. This study was carried out to identify and evaluate the antagonistic activity of actinomycetes from mangrove sediment against Escherichia coli and Staphylococcus aureus. Identification of actinomycetes was performed based on morphological dan physiological characters. The antagonistic test was carried out against Escherichia coli and Staphylococcus aureus. A total of ten isolates had been successfully isolated and grouped into eight genera, including; Oerskovia H1, Micrococcus H2, Nocardia H3, Sporichtya H5, Corynebacterium H6, Jonesia H7, Actinomyces H10, and Streptomyces H8, H11, H12. Actinomycetes from mangrove sediment were gram-positive bacillus. The shape of the colony varied from circular to filamentous and irregular, with medium and large colony sizes. The colony appears white or yellow. The surface is convex and flat, aerobes and facultative anaerobes; capable of fermenting glucose. Five isolates have very strong growth inhibition activity against E. coli: Nocardia H3 (27.81mm ± 1.39), Actinomycetes H10 (27.75mm ± 2.48), Corynebacterium H6 (27.69mm ± 2.39), Micrococcus H2 (18.55mm ± 2.44), and Streptomyces H8 (17.92mm ± 2.70) while Streptomyces H8 (24.83mm ± 2.08), and Actinomycetes H10 (16.06mm ± 2.49) were active against S. aureus.