Natural Colonies Research Articles

Estimate of complexity of behavioral patterns in ants: analysis of hunting behavior in Myrmica rubra (Hymenoptera, Formicidae) as an example

A method for estimating the complexity of behavioral patterns of ants based on the Kolmogorov complexity is considered. Behavioral sequences are presented as “texts” compressed with the KGB Archiver (v. 1.2). The elements of behavior (a total of 10) singled out from video records served as an alphabet. The comparison of “successful” and “incomplete” hunting behaviors in Myrmica rubra showed that successful hunting patterns were characterized by less complexity than “incomplete” ones. It was assumed that complete patterns had less redundancy and better predictability. The smallest complexity was revealed in complete hunting patterns of naive (laboratory reared) ants in comparison with members of a natural colony. In perspective, quantitative evaluation of complexity of behavioral patterns will help to evaluate the level of discrete variability within ant colonies.

Spread of plague among black‐tailed prairie dogs is associated with colony spatial characteristics

AbstractSylvatic plague (Yersinia pestis) is an exotic pathogen that is highly virulent in black‐tailed prairie dogs (Cynomys ludovicianus) and causes widespread colony losses and individual mortality rates >95%. We investigated colony spatial characteristics that may influence inter‐colony transmission of plague at 3 prairie dog colony complexes in the Great Plains. The 4 spatial characteristics we considered include: colony size, Euclidean distance to nearest neighboring colony, colony proximity index, and distance to nearest drainage (dispersal) corridor. We used multi‐state mark–recapture models to determine the relationship between these colony characteristics and probability of plague transmission among prairie dog colonies. Annual mapping of colonies and mark–recapture analyses of disease dynamics in natural colonies led to 4 main results: 1) plague outbreaks exhibited high spatial and temporal variation, 2) the site of initiation of epizootic plague may have substantially influenced the subsequent inter‐colony spread of plague, 3) the long‐term effect of plague on individual colonies differed among sites because of how individuals and colonies were distributed, and 4) colony spatial characteristics were related to the probability of infection at all sites although the relative importance and direction of relationships varied among sites. Our findings suggest that conventional prairie dog conservation management strategies, including promoting large, highly connected colonies, may need to be altered in the presence of plague. © 2011 The Wildlife Society

Observational Learning in a Glaucous-winged Gull Natural Colony

The ability of the Glaucous-winged Gull (Larus glaucescens) to observationally learn has been investigated in their natural habitat, in a gull’s colony located on Toporkov Island (Comandorsky State Nature Reserve, Far East, Russia). The experiment was carried out in the gull’s breeding period, when each bird’s pair in the colony occupies and protects vigilantly their small nesting sites surrounded by those of neighboring pairs. The gulls chosen to be demonstrators were trained to solve two different tasks both of which were not part of the species’ behavioral repertoire. The first task was obtaining a bait placed by an experimenter into an opaque box within the bird's visual field ; the second one was choosing a red box from a set of four identically-looking boxes differing only incolor. In contrast to the demonstrator gulls, which needed considerably training, most observers (the gulls nesting side-by-side with the demonstrators) performed the same tasks correctly in the first trial.Thus, gulls have proven to be capable of successful learning to solve simple choice tasks by observing what their conspecifics are doing. Observational learning can be a way to distribute individual experience among the gulls in a colony. The ability to observationally learn quickly maybe one of the factors underlying a higher adaptive potential of these birds.

Caste development systems of the Neotropical termite Constrictotermes cyphergaster (Isoptera, Termitidae)

The caste developmental system of the Neotropical termite Constrictotermes cyphergaster was investigated in 12 natural colonies from the semi-arid Caatinga region of northeastern Brazil. Twelve measurements were taken of different body parts of the larvae, workers, presoldiers, soldiers, nymphs, and alates for morphometric analyses, and principal component analyses (PCA) were performed based on these parameters. The nymphal line comprised one larval instar, followed by five nymphal instars, and alates, in agreement with the developmental pattern described for Termitidae species. The apterous line included two larval instars, followed by workers, presoldiers, and soldiers. Both workers and soldiers were found to be monomorphic and composed only of male specimens, with only one instar phase each. C. cyphergaster, like most of the Nasutitermitinae, has only male soldiers. The presence of male workers, with only one instar, suggests a simplified system of differentiation in the apterous line of C. cyphergaster. These patterns, which had not previously been described for ‘full nasute’ Nasutitermitinae, are similar to the differentiation patterns of the ‘mandibulate nasute’ Cornitermes walkeri.

Hitchhiking and the removal of microbial contaminants by the leaf‐cutting ant Atta colombica

1. The ecologically dominant leaf‐cutting ants exhibit one of the most complex forms of morphological caste‐based division of labour in order to efficiently conduct tasks, ranging from harvesting fresh leaf material to caring for the vulnerable fungal crop they farm as food. While much of their division of labour is well known, the role of the smallest workers on foraging trails is puzzling. Frequently these minim workers hitchhike on leaf fragments and it has been suggested that they may act to reduce the microbial contamination of leaf material before they enter the nest. Here we investigated this potentially important role of minims with field colonies of Atta colombica.2. We experimentally increased the microbial load of leaf fragments and found that this resulted in minims hitchhiking on leaf fragments for longer. Furthermore, we show that leaves naturally have a significant microbial load and that the presence of hitchhikers reduces the microbial load of both experimentally manipulated and natural leaf fragments.3. Intriguingly, the microbial load of leaves high in the canopy where ants were foraging was much lower than closer to the ground where the ants avoided cutting leaves. This suggests that the often perplexing foraging patterns of leaf‐cutting ants may in part be explained by the ants avoiding leaves that are more heavily contaminated with microbes.4. The removal of microbial contaminants is therefore an important role of hitchhiking minim workers in natural colonies of Atta leaf‐cutting ants, although other tasks such as trail maintenance and defence also explain their occurrence on trails.

Sex-Ratio Bias in Alates of Polygyne Colonies of the Red Imported Fire Ant Solenopsis invicta Buren (Hymenoptera: Formicidae) in China

A sex-ratio bias was studied in alates of natural polygyne colonies of Solenopsis invicta Buren in southern China. The results showed that at the population level, the numbers of male and female alates were nearly equal, even though there was a strong bias toward producing one particular sex at the nest level. For example, 88.89% of the nests sampled were strongly biased toward males or females. In particular, three bias types were observed: extreme female bias, extreme male bias, and a moderate bias. Future studies should address the factors that lead queens to produce strongly biased sex ratios.

Between-year stability of individual alarm calls in the yellow ground squirrelSpermophilus fulvus

Although individuality in alarm calls has been reported for many ground-dwelling sciurids, the degree to which the vocal identity encoded in alarm calls is stable with time has been studied only for a single sciurid species. Thus, no comparable data are available. We examined the retention of the vocal keys to individual identity after hibernation in a natural colony of yellow ground squirrels (Spermophilus fulvus), long-lived, obligate-hibernating rodents that maintain stable social groups for years. We recorded alarm calls in 2 subsequent years, separated by hibernation, from 22 individually marked animals. All individuals could be distinguished with high probability by their alarm calls within a year. However, only 6 of the 22 animals kept their alarm calls stable after hibernation. Sex, age, year of data collection, and the distance that individuals moved between years did not have significant effects on the retention of a stable alarm call structure after hibernation. Given the low proportion of individuals with stable alarm calls, vocal identity cannot be the only modality sufficient to secure the recovery of personalized social relationships after hibernation in the yellow ground squirrel.

Histological assessment of cellular immune response to the phytohemagglutinin skin test in Brazilian free-tailed bats (Tadarida brasiliensis)

Bats are known reservoirs for numerous emerging infectious diseases, occupy unique ecological niches, and occur globally except for Antarctica. Given their impact on human and agricultural health, it is critical to understand the mechanisms underlying immunocompetence in this reservoir host. To date, few studies have examined immune function in the Order Chiroptera, particularly among natural colonies of bats. The phytohemagglutinin (PHA) skin test has been widely used to measure delayed-type cellular immune response in a wide variety of vertebrates, and has been routinely employed in immunoecological studies. Although this test is frequently described as a measure of T cell proliferation, recent studies indicate it may represent a combination of immune responses. In mammals, the immune response is differentially, temporally and spatially regulated, therefore, we characterized the infiltrating leukocyte response to the PHA skin test in bats by examining a time-series of histological sections from PHA and saline injection areas in 41 Brazilian free-tailed bats (Tadarida brasiliensis). Results suggest that bats exhibit diverse leukocyte traffic within 6 h, and up to 24 h following subcutaneous PHA injection. There was a significant presence of lymphocytes and neutrophils, as well as eosinophils, basophils, and macrophages observed in the PHA-injected tissues, compared with saline-injected control tissues. We observed a highly significant negative correlation between the number of lymphocytes and neutrophils in PHA-injected tissue, with peak lymphocyte response at 12 h, and peak neutrophil response at 24 h post-injection. These results indicate substantial variation in the immune response of individuals, and may aid our understanding of disease emergence in natural populations of bats.

Collective defense of Aphis nerii and Uroleucon hypochoeridis (Homoptera, Aphididae) against natural enemies.

The prevalent way aphids accomplish colony defense against natural enemies is a mutualistic relationship with ants or the occurrence of a specialised soldier caste typcial for eusocial aphids, or even both. Despite a group-living life style of those aphid species lacking these defense lines, communal defense against natural predators has not yet been observed there. Individuals of Aphis nerii (Oleander aphid) and Uroleucon hypochoeridis, an aphid species feeding on Hypochoeris radicata (hairy cat's ear), show a behavioral response to visual stimulation in the form of spinning or twitching, which is often accompanied by coordinated kicks executed with hind legs. Interestingly, this behaviour is highly synchronized among members of a colony and repetitive visual stimulation caused strong habituation. Observations of natural aphid colonies revealed that a collective twitching and kicking response (CTKR) was frequently evoked during oviposition attempts of the parasitoid wasp Aphidius colemani and during attacks of aphidophagous larvae. CTKR effectively interrupted oviposition attempts of this parasitoid wasp and even repelled this parasitoid from colonies after evoking consecutive CTKRs. In contrast, solitary feeding A. nerii individuals were not able to successfully repel this parasitoid wasp. In addition, CTKR was also evoked through gentle substrate vibrations. Laser vibrometry of the substrate revealed twitching-associated vibrations that form a train of sharp acceleration peaks in the course of a CTKR. This suggests that visual signals in combination with twitching-related substrate vibrations may play an important role in synchronising defense among members of a colony. In both aphid species collective defense in encounters with different natural enemies was executed in a stereotypical way and was similar to CTKR evoked through visual stimulation. This cooperative defense behavior provides an example of a surprising sociality that can be found in some aphid species that are not expected to be social at all.

Complementary UV-Absorption of Mycosporine-like Amino Acids and Scytonemin is Responsible for the UV-Insensitivity of Photosynthesis in Nostoc flagelliforme

Mycosporine-like amino acids (MAAs) and scytonemin are UV-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. Natural colonies of the UV-insensitive Nostoc flagelliforme were found to be especially rich in MAAs (32.1 mg g DW−1), concentrated in the glycan sheath together with scytonemin. MAAs are present in the form of oligosaccharide-linked molecules. Photosystem II activity, measured using PAM fluorescence and oxygen evolution, was used as a most sensitive physiological parameter to analyse the effectiveness of UV-protection. Laboratory experiments were performed under controlled conditions with a simulated solar radiation specifically deprived of UV-wavebands with cut-off filters (295, 305, 320, 345 and 395 nm). The UV-insensitivity of N. flagelliforme was found to cover the whole UV-A (315–400 nm) and UV-B (280–320 nm) range and is almost certainly due to the complementary UV-absorption of MAAs and scytonemin. The experimental approach used is proposed to be suitable for the comparison of the UV-protection ability in organisms that differ in their complement of UV-sunscreen compounds. Furthermore, this study performed with a genuinely terrestrial organism points to the relevance of marine photoprotective compounds for life on Earth, especially for the colonization of terrestrial environments.

A stingless bee hive design for a broader climate range

Stingless bees, managed hives, colony health, hive design Journal of Apicultural Research 49(3): 290-292 (2010) © IBRA 2010 DOI: 10.3896/IBRA.1.49.3.11 The increased interest in pollination services provided by Australian stingless bees (Heard, 2001) and increased interest from crop growers (Pintus, L. and Hannah, L. pers comm.) is creating the need for improved maintenance of stingless bee colonies in areas that are beyond the bees’ natural, geographic distribution, which is along the northern coast of Australia and down the eastern coast to Bega (lat. 37oS). It is, therefore, important that stingless bee hive designs keep improving to provide better protection against adverse climatic conditions, thus enhancing the chances of colony survival in areas with temperate climates (Slaa et al., 2006; Dollin, 2007). Many natural colonies of Trigona carbonaria and Austroplebeia australis are found in temperate regions (Michener, 2000) and are able to survive in these regions, because they nest in logs that offer good insulation against extremes of temperature (Dollin, 2007; Dollin and Sakagami 1997; Macieira and Proni 2004; Roubik 2006). The hive designs currently in use (Heard 1988) are, however, better suited to tropical and subtropical areas and may not provide sufficient insulation for the periods of extreme hot and cold experienced in temperate regions. Here, a new design, the Temperate Climate (TC) hive, emulating successful, natural, stingless bee nesting sites found in temperate regions was compared with the Original Australian Trigona Hive (OATH) that is commonly used in tropical and subtropical areas of Australia. Similar to the OATH hive, the TC hive is light, compact, easy to construct and enables propagation of colonies by separation of the top box. Unlike the solid timber of the OATH hive, however, it is made from inexpensive, hollow, humidity-resistant, external door panelling (Fig. 1a). In contrast to the OATH hive, worker bees can access the feeder box by a transit tube, which helps prevent feeder robbing, and the hive has a honey super that is accessed internally via a queen excluding slot in the top box. The internal and external casings are separated by a 30 mm air gap, which has 10 mm holes that can be opened or closed manually to enable air to circulate as ventilation during temperature extremes. The internal dimensions allocated for brood rearing are 120 mm x 120 mm x 120 mm (1,728,000 mm

Counts and breeding success of Black- legged Kittiwakes Rissa tridactyla nesting on man-made structures along the River Tyne, northeast England, 1994-2009

Numbers of Black-legged Kittiwakes Rissa tridactyla nesting up to 17 km inland on man-made structures along the River Tyne, northeast England, ranged between 72 and 531 successful nests (those raising at least one well-grown chick) from 1994 to 2009, and 465–755 apparently occupied nests in 2000–09. The number of pairs each year was influenced by the availability of suitable nesting sites, in turn affected by man’s efforts to deter birds from certain buildings. While breeding success was influenced by local summer weather in some years, being suppressed by heavy rainfall, it compared favourably with natural colony sites along the coast of northeast England.

Scheduling Resource-Constrained Projects with Ant Colony Optimization Artificial Agents

The paper presents a methodology to schedule resource-constrained construction projects by use of algorithms based on ant colony optimization (ACO); an artificial agent inspired by the collective behavior of natural ant colonies as they optimize their path from an origin (ant nest) to a destination (food source) by use of previously acquired knowledge. Further, to an application of the ACO artificial agent to a resource-unconstrained network topology, the method is applied to a resource-constrained network and utilized in examining the effects of resource availability constraints to critical path calculations and project completion time.

Juvenile Hormone titre and vitellogenin gene expression related to ovarian development in primary reproductives compared with nymphs and nymphoid reproductives of the termiteReticulitermes speratus

To elucidate the reproductive cycle of termite queens, incipient colonies of Reticulitemes speratus (Isoptera: Rhinotermitidae) are established under laboratory conditions, and the transition of colony development is observed at 0.5, 1.5, 2.5, 3.5, and 7.5 months (stages I–V, respectively) after colony foundation. Ovarian development, vitellogenin gene expression and Juvenile Hormone (JH) titres are examined in the queens and in nonphysogastric nymphoids collected from natural colonies. A reproductive cycle in queens is observed, in which the oviposition rate is relatively higher during stages I and II, and then decreases during stages III and IV. Vitellogenic oocytes are not observed in the ovaries during stages III and IV, and the expression level of the vitellogenin gene is low, suggesting that egg production in queens is repressed during these stages. However, vitellogenin gene expression and egg deposition in queens resumes during stage V. Juvenile Hormone levels rise during the transition from nymphs to stage I queens, and elevated JH titres are observed also during stages III and IV. The decrease in JH titre in queens at stage II precedes the decline in vitellogenesis at stages III and IV. Thus, JH titre and vitellogenesis are correlated in an offset pattern. However, nonphysogastric nymphoid reproductives do not have vitellogenic oocytes in their ovaries, and their JH titre is two-fold higher than that of queens, suggesting that elevated JH titre precedes vitellogenesis, as in queens.

Correlates of viral richness in bats (order Chiroptera).

Historic and contemporary host ecology and evolutionary dynamics have profound impacts on viral diversity, virulence, and associated disease emergence. Bats have been recognized as reservoirs for several emerging viral pathogens, and are unique among mammals in their vagility, potential for long-distance dispersal, and often very large, colonial populations. We investigate the relative influences of host ecology and population genetic structure for predictions of viral richness in relevant reservoir species. We test the hypothesis that host geographic range area, distribution, population genetic structure, migratory behavior, International Union for Conservation of Nature and Natural Resources (IUCN) threat status, body mass, and colony size, are associated with known viral richness in bats. We analyze host traits and viral richness in a generalized linear regression model framework, and include a correction for sampling effort and phylogeny. We find evidence that sampling effort, IUCN status, and population genetic structure correlate with observed viral species richness in bats, and that these associations are independent of phylogeny. This study is an important first step in understanding the mechanisms that promote viral richness in reservoir species, and may aid in predicting the emergence of viral zoonoses from bats.

Microsatellite DNA polymorphisms for colony management of longtailed macaques (Macaca fascicularis) population on the Tinjil Island

Perwitasari-Farajallah D, Kyes RC, Iskandar E (2010) Microsatellite DNA polymorphisms for colony management of long-tailed macaques (Macaca fascicularis) population on the Tinjil Island. Biodiversitas 11: 55-58. Polymorphic genetic markers are the basic requirement for studies on population and conservation genetics of non-human primates. In this paper, we screened microsatellites for their polymorphism and gene typing of DNA samples from blood of wild long-tailed macaques (Macaca fascicularis) from Tinjil Island population. Among the three primer sets tested, two are polymorphic. They were D1S548 and D3S1768. Average observed heterozygosity (Ĥ) within populations ranged between 0.264-0.555. D1S1768 locus was highly polymorphic and 24 alleles were detected among two loci. Estimation of genetic variability for the Tinjil population (Ĥ) was 0.485. The results obtained provide furtherinsight into the long-term viability of the population and help in creating genetic management of both captive and natural habitat breeding colonies of primates.Key words: microsatellite, variations, social groups, long-tailed macaques, Macaca fascicularis

Behavioral evolution in the major worker subcaste of twig-nesting Pheidole (Hymenoptera: Formicidae): does morphological specialization influence task plasticity?

Polymorphism frequently correlates with specialized labor in social insects, but extreme morphologies may compromise behavioral flexibility and thus limit caste evolution. The ant genus Pheidole has dimorphic worker subcastes in which major workers appear limited due to their morphology to performing defensive or trophic functions, thus providing an ideal model to investigate specialization and plasticity. We examined worker morphology, brood-care flexibility, and subcaste ratio in 17 species of tropical twig-nesting Pheidole by quantifying nursing by major workers in natural colonies and in subcolonies lacking minors, in which we also measured brood survival and growth. Across species, majors performed significantly less brood care than minors in intact colonies, but increased rates of brood care 20-fold in subcolonies lacking minors. Brood nursed by majors had lower survival than brood tended by minors, although rates of brood growth did not vary between subcastes. Significant interspecific variation in rates of brood care by major workers did not lead to significant differences in brood growth or survival. Additionally, we did not find a significant association between the degree of major worker morphometric specialization and rates of nursing, growth, or survival of brood among species. Therefore, major workers showed reduced efficacy of brood care, but the degree of morphological specialization among species did not directly compromise task plasticity. The compact nests and all-or-nothing consequences of predation or disturbance on colony fitness may have influenced the evolution of major worker brood-care competency in twig-nesting Pheidole.

Parentage and relatedness in captive and natural populations of the Roseate Spoonbill (Aves: Ciconiiformes) based on microsatellite data

This study constitutes a first approach to evaluate the use of genetic information and relatedness estimators in the investigation of questions related to mating system and parentage in ex situ and in situ populations of the Roseate Spoonbill. We assessed the parentage assignments in 17 supposed families from US captive populations and investigated the genetic relationships among 67 nestlings sampled within 28 nests in Brazilian natural breeding colonies. Estimations of genetic relatedness values, hypothesis testing methods, simulations and maximum likelihood approaches were performed on data from four microsatellite loci. Parentage was confirmed in 61.5% of the registered parent-offspring relationships at zoo parks. Inconsistencies in assignments were investigated and the likely parents were identified for most of the hatchlings. Matings among relatives, not previously noticed based on behavioral observations, were identified by the use of genetic analyses. In natural populations, 33% of the sampled dyads were confidently classified as full-sibs. Above 25% of the analyzed dyads were unrelated, indicating that more than one parent-pair may have been responsible for the progeny. Our results demonstrate that genetic information can augment the precision in parentage assignment in captive Roseate Spoonbill populations, and this approach can contribute to their management and conservation. Results obtained using three different methodologies are concordant and point to the existence of a mating system other than monogamy for this species in the wild. The approaches implemented in this study can be applied to other waterbird species in which capture of adults is difficult.

De novo establishment of wild-type song culture in the zebra finch.

What sort of culture would evolve in an island colony of naive founders? This question cannot be studied experimentally in humans. We performed the analogous experiment using socially learned birdsong. Culture is typically viewed as consisting of traits inherited epigenetically, via social learning. However, cultural diversity has species-typical constraints1, presumably of genetic origin. A celebrated, if contentious, example is whether a universal grammar constrains syntactic diversity in human languages2. Oscine songbirds exhibit song learning and provide biologically tractable models of culture: members of a species show individual variation in song3 and geographically separated groups have local song dialects 4,5. Different species exhibit distinct song cultures6,7, suggestive of genetic constraints8,9. Absent such constraints, innovations and copying errors should cause unbounded variation over multiple generations or geographical distance, contrary to observations9. We asked if wild-type song culture might emerge over multiple generations in an isolated colony founded by isolates, and if so, how this might happen and what type of social environment is required10. Zebra finch isolates, unexposed to singing males during development, produce song with characteristics that differ from the wild-type song found in laboratory11 or natural colonies. In tutoring lineages starting from isolate founders, we quantified alterations in song across tutoring generations in two social environments: tutor-pupil pairs in sound-isolated chambers and an isolated semi-natural colony. In both settings, juveniles imitated the isolate tutors, but changed certain characteristics of the songs. These alterations accumulated over learning generations. Consequently, songs evolved toward the wild-type in 3–4 generations. Thus, species-typical song culture can appear de novo. Our study has parallels with language change and evolution12,13. In analogy to models in quantitative genetics14,15, we model song culture as a multi-generational phenotype, partly encoded genetically in an isolate founding population, influenced by environmental variables, and taking multiple generations to emerge.

Effective paternity in natural colonies of Japanese native bumble bees

AbstractKin selection theory predicts a high coefficient of genetic relatedness among nestmates, explaining the frequent evolution of eusociality in a social hymenopteran colony. The bumble bee is a primitively eusocial hymenoptera whose colonies are founded by a single queen. In such a monogynous colony, mating frequency of the queen is the sole factor that affects genetic relatedness among nestmates. Although the queens of most bumble bee species are known to be monandrous, there are some species that are known to be polyandrous. Here, we estimated the effective paternity in the native colonies of Japanese bumble bees, Bombus ardens, B. diversus, and B. honshuensis, using genetic polymorphic data of microsatellites. We found no evidence for polyandry in any investigated colonies, which suggests that within‐colony genetic relatedness is very high for all of these colonies.