Absence of cuticular alkenes allows lycaenid larvae to avoid predation by Formica japonica ants

Chemical mimicry and camouflage based on cuticular hydrocarbons (CHCs) are adaptive strategies that are frequently observed in myrmecophilous insects. The larvae of several lycaenid butterfly species that exhibit obligate associations with specific ant species have been reported to use chemical mimicry. However, little is known about the strategies used by the larvae of species that have facultative associations with multiple ant species. We attempted to reveal the effects of larval CHC profiles on interactions with Formica japonica workers, using three lycaenid species, two facultative ant‐associated (Lycaeides argyrognomon and Zizeeria maha) and one non‐ant‐associated (Lycaena phlaeas), which commonly possess n‐alkanes as the major CHCs. In field bioassays, the lycaenid larvae were attacked by ant workers less often than larvae of Papilio polytes (Papilionidae), the CHCs of which were rich in 7‐alkenes. Treating the lycaenid larvae with 7‐heptacosene and 9‐heptacosene significantly activated ant aggression (biting), whereas treating them with n‐heptacosane, n‐octacosane and 13‐methylheptacosane had little effect. Furthermore, larvae of Pieris rapae (Pieridae), possessing n‐alkanes as the dominant CHCs, suffered an intermediate level of ant biting between the lycaenid and Pa. polytes larvae. However, treatments of the P. rapae larvae with 7‐heptacosene and 9‐heptacosene significantly affected the frequency of ant biting. These findings suggest that the absence of alkenes in larval CHC profiles is an effective means of circumventing predation by ants and allows lycaenid larvae to inhabit the foraging territory of predaceous ants, at least to some extent.     

The occurrence rate of ants from the Formica rufa-group in various phytosociologic associations

Summary During the inventory of ant heaps of the group Formica rufa, performed in the years 1972–73 in the Wielkopolski National Park near Pozna, it was found that the vegetal cover composition, determining to a large extent phytosociologic associations, is likely not so important to ants as the dominant stand. First of all, the specific composition of trees determines not only the degree of the forest bottom shade, but also the specific composition of aphids, constituting an important link in trophic alliances, and, besides that, assuring the corresponding composition of food for ants in the form of phytophages.     

Correction to: Route reassessment by transporter ants improves speed and directional accuracy of cooperative transport in Formica japonica

Journal of Ethology - The article Route reassessment by transporter ants improves speed and directional accuracy of cooperative transport in Formica japonica, written by Shumpei Hisamoto, Natsumi...     

Protective behavior or ‘true’ tool use? Scrutinizing the tool use behavior of ants

In the genus Aphaenogaster, workers use tools to transport liquid food to the colony. During this behavior, ants place or drop various kinds of debris into liquids or soft food, and then, they carry the food‐soaked tools back to the nest. According to some authors, this behavior is not "true" tool use because it represents two separate processes: a defense response to cover the dangerous liquid and a transport of food. Here, we investigated the debris dropping and retrieving behavior of the ant Aphaenogaster subterranea to establish which of the two hypotheses is more probable by conducting manipulative experiments. We tested the responses of eight colonies (a) to liquid food (honey‐water) and nonfood liquids (water) in different distances from the nest and (b) to nonthreatening liquids previously covered or presented as small droplets. We also tested whether the nutritional condition of colonies (i.e., starved or satiated) would affect the intensity and rate of debris dropping. Our results were consistent with the tool‐using behavior hypothesis. Firstly, ants clearly differentiated between honey‐water and water, and they directed more of their foraging effort toward liquids farther from the nest. Secondly, ants performed object dropping even into liquids that did not pose the danger of drowning or becoming entangled. Lastly, the nutritional condition of colonies had a significant effect on the intensity and rate of object dropping, but in the opposite direction than we expected. Our results suggest that the foraging behavior of A. subterranea is more complex than that predicted by the two‐component behavior hypothesis and deserves to be considered as "true" tool use.     

Wood ants are wood ants: deforestation causes population declines in the polydomous wood ant Formica aquilonia

Abstract.  1. One of the main themes in ecology is adaptation for survival in different habitats and the potential of the environment to regulate populations.
2. The effects of clear-cutting on nest-abandonment rate and local population sizes in the polydomous wood ant Formica aquilonia was studied, using uncut forest stands as controls.
3. The nest-abandonment rate was clearly higher in clear-cuts than in forest interiors. In clear-cuts, 39% of pre-deforestation nests and 73% of new bud-nests were abandoned 4–5 years after deforestation, whereas in forest interiors fewer than 2% of nests were abandoned at the same time period. Local population size decreased 30% in clear-cuts, but fewer than 2% in forest interiors.
4. The results demonstrate that despite modern logging practices in which mechanical harming of nest mounds is reduced, nest mounds are abandoned at high rate, and despite frequent establishment of new bud-nests, populations start to decline.
5. The likely reason for the high nest-abandonment rate in clear-cuts is a combination of changed abiotic conditions, resource limitation, and disturbed reproduction.
6. Species that are sensitive to changes in the size of habitat patch, such as F. aquilonia , likely are harmed by logging, even employing biodiversity oriented management practices. Hence there is a need for conservation actions that are based on the size of protection areas.     

Nest relocation in the slavemaking ants Formica subintegra and Formica pergandei: a response to host nest availability that increases raiding success

Social insects typically occupy spatially fixed nests which may thus constrain their mobility. Nevertheless, colony movements are a frequent component of the life cycle of many social insects, particularly ants. Nest relocation in ants may be driven by a variety of factors, including nest deterioration, seasonality, disturbances, changes in microclimate, and local depletion of resources. The colony movements of slavemaking ants have been noted anecdotally, and in recent studies such relocations were primarily attributed to nest deterioration or shifts to overwintering locations. In this study we explore nest relocations in large colonies of formicine slavemakers which occupy stable and persistent earthen nest mounds. We investigate the hypothesis that colony relocations of these slavemakers are best explained by efforts to improve raiding success by seeking areas of higher host availability. Five summers of monitoring the raiding behavior of 11–14 colonies of the slavemakers Formica subintegra and Formica pergandei revealed relatively frequent nest relocations: of 14 colonies that have been tracked for at least three of 5 years, all but one moved at least once by invading existing host nests. Movements tended to occur in the middle of the raiding season and were typically followed by continued raiding of nearby host colonies. Spatial patterns of movements suggest that their purpose is to gain access to more host colonies to raid: the distance moved is typically farther than the mean raiding distance before the move, which may indicate an effort to escape their local neighborhood. Furthermore, the mean distance of raids after relocation is shorter than the distance before relocation. For many slavemaking ant colonies, particularly those on the verge of relocating, raiding distance increased as the raiding season progressed. In addition, movements tended to be toward areas of higher local host density. Nest relocation is likely an important component of the ecology of slavemaking ants that contributes to the dynamic nature of their interaction with the host ant population.     

A comparative study of egg recognition signature mixtures in Formica ants

Processing of information from the environment, such as assessing group membership in social contexts, is a major determinant of inclusive fitness. For social insects, recognizing brood origin is crucial for inclusive fitness in many contexts, such as social parasitism and kin conflicts within colonies. Whether a recognition signature is informative in kin conflicts depends on the extent of a genetic contribution into the cues. We investigated colony‐ and matriline‐specific variation in egg surface hydrocarbons in seven species of Formica ants. We show that chemical variance is distributed similarly to genetic variation, suggesting a significant genetic contribution to eggs odors in the genus. Significant among matriline components, and significant correlations between chemical and genetic similarity among individuals also indicate kin informative egg odors in several species. We suggest that egg odor surface variation could play a large role in within colony conflicts, and that a comparative method can reveal novel insight into communication of identity.     

The biological race concept as a research tool

In present day research in human biology, the validity of the concept of biological race rests on its utility as a research tool. The methodology of this research into human biological variability is a multidimensional application of the comparative method, utilizing, as one dimension, genetic distance. The body of this paper suggests two generalizing principles for the establishment of genetic distance. Genetic distance may occur due to physical or temporal isolation or in conjunction with environmental differences. A brief analysis of the fifteenth century human populations examines the relationship between these principles and presently used racial taxonomic systems. It is concluded that race may be defined operationally as a rough measure of genetic distance in human populations and as such may function as an informational construct in the multidisciplinary area of research in human biology.     

Genetic changes associated to declining populations of Formica ants in fragmented forest landscape

We monitored populations of two wood ant species, Formica aquilonia and Formica lugubris, through annual mapping of the colonies in a fragmenting forest landscape from 1966 to 1998. The genetic population structure was studied at the end of the study period by using 12 microsatellite loci. Fragmentation of forest led to a decline and spatial redistribution of populations. Changes in the spatial distribution were particularly pronounced in the highly polygynous (many queens in a single nest) species F. aquilonia, whose local populations declined or became extinct, or relocated themselves and colonized new patches. The genetic relationships of the remaining subpopulations indicated the historical developments, revealing the boundaries of the historical populations (high values of genetic differentiation, F(ST)), recolonization histories (genetic affinities revealed by Bayesian analyses) and population decline (reduced variation). Big genetic differences could be detected over short distances, so differentiation also depended on social factors. Our results showed that a genetic study can be reliably used to dissect the recent historical changes underlying the present population structure, and that species with different social structures can respond differently to habitat changes. Combining our demographic and genetic results suggests that habitat fragmentation forms a clear threat on a local scale with large negative effects on ant population viability.     

Octopaminergic system in the brain controls aggressive motivation in the ant, Formica japonica

The ant, Formica japonica, is polyphagous and workers hunt other insects as foods. In this study, interspecific aggression was examined in the workers and queens. Behavior experiments demonstrated that interspecific aggressiveness was significantly higher in workers than queens. Workers showed predatory aggressive behavior towards crickets, on the other hand, queens elicited threat behavior but they didn't attack crickets. In order to investigate neuronal mechanisms underlying regulation of aggressive motivation, the role of biogenic amine in the brain in evoking aggressive behavior was examined by measuring biogenic amine using high-performance liquid chromatography (HPLC) with electrochemical detection (ECD). No significant difference in the octopamine (OA) level was found between workers and queens, but the level of N-acetyloctopamine (NacOA) in the brain of queens was significantly higher than that of workers. This study suggests that OAergic system in the brain must involve in controlling aggressive motivation in the ants.     

Characterization of microsatellite loci in red wood ants Formica (s. str.) spp. and the related genus Polyergus

Ants are interesting subjects for studies of evolution of altruism. We developed 13 microsatellite loci in a red wood ant Formica (s. str.) yessensis from random amplified polymorphic DNA fragments to study genetic structure within populations and colonies. Five loci bore two to five alleles in both F. (s. str.) yessensis and F. (s. str.) truncorum and two were also polymorphic in a related species, Polyergus samurai. Results suggest that the loci will be useful in evolutionary studies on Formica and Polyergus species.     

Polygyny and Monoandry in the Ant Formica japonica (Hymenoptera: Formicidae)

Queen number, mating frequency and nest kin-structure of the ant Formica japonica were studied in the field and the laboratory. Nest excavation in the study site, the east slope of Mt. Fuji, Gotenba, Japan, revealed that F. japonica is weakly polygynous all year round and the queen number increases after the nuptial flight season, suggesting the adoption of newly mated queens by established nests. Dissection and laboratory rearing demonstrated that nearly all queens in polygynous nests had mated and were fertile with mature oocytes in their ovaries. Multilocus DNA fingerprinting was used to examine kin relationships among ants found in the same nests. The fingerprint band patterns were apparently governed by a simple genetic rule and suggested monoandry (single mating per queen). The mean band sharing score of DNA fingerprints among full sisters was 0.90, and the mean value between queens and their daughters was 0.75. Comparison of DNA fingerprints of adult and pupal workers with pupal gynes suggested that multiple queens in a nest may contribute unequally to gyne (new queen) production.     

The emergence of the social‐ecological restoration concept

Many ecosystems in the world are the result of a close interaction between local people and their environment, which are currently recognized as social‐ecological systems (SoES). Natural catastrophes or long‐standing social and political turmoil can degrade these SoES to a point where human societies are no longer autonomous and their supporting ecosystems are highly degraded. Here, we focus on the special case of the restoration of SoES that we call social‐ecological restoration (SoER), which is characterized as a restoration process that cannot avoid simultaneously dealing with ecological and social issues. In practice, SoER is analogous in many ways to the general principles of ecological restoration, but it differs in three key aspects: (1) the first actions may be initially intended for human groups that need to recover minimum living standards; (2) the SoER process would often be part of a healing process for local people where cultural values of ecosystems play an essential role; and (3) there is a strong dependency on external economic inputs, as the people belonging to the SoES may be incapable of reorganizing themselves on their own and supporting ecosystems can no longer self‐recover. Although it might not be desirable or necessary to call all restoration projects with a social component an SoER, the use of this concept may help in defining early restoration targets that may prevent conflicts among users in the long term. From the perspective of other disciplines, SoER would be more appropriately perceived as programs of “social‐ecological recovery” in the long term.     

Abundance and distribution of organic mound-building ants of the Formica rufa group in Yellowstone National Park

Red wood ants (Formica rufa group) are ubiquitous in many conifer and mixed‐conifer forests of northern Europe and Asia. In contrast, relatively little is known about the abundance and distribution of the 24 North American F. rufa group species. As ants are important components of most soil invertebrate communities and are considered ecosystem engineers that alter the flow of energy and nutrients through terrestrial systems, it is important to gain information on their distribution and abundance. We conducted a survey for red wood ant mounds in Yellowstone National Park (YNP), Wyoming/Montana, USA, where human disturbance has been kept to a minimum for over 130 years. We found a total of 85 red wood ant mounds (0.11 to 0.17 mounds/ha) on 327 km of roads and 180 km of the hiking trails we surveyed. The occurrence of ant mounds was higher then expected by random distribution at elevations between 1600 and 2400 m, annual precipitation of 250 to 760 mm, middle and late successional lodgepole pine, late successional Douglas fir forest and non‐forested grassland/sagebrush prairie vegetation. Additionally, mounds were clustered in gently sloped not north‐exposed locations and in areas that had not recently burned. Most of the mounds detected were inhabited by Formica obscuripes Forel, which occupied 94% of the mounds sampled. Based on a multi‐criteria binary Geographic Information System model that we developed, we found that ant mounds were to be expected with a high probability in less then 1% of the YNP area. These results together with the detected low density and small size of the red wood ant mounds within the study area suggest that these insects have a much lower impact on invertebrate biodiversity and ecosystem processes, such as forest productivity and carbon and nutrient cycling on the ecosystem scale compared with their counterparts in European or Asian systems.     

Eliminating the mystery from the concept of emergence

While some branches of complexity theory are advancing rapidly, the same cannot be said for our understanding of emergence. Despite a complete knowledge of the rules underlying the interactions between the parts of many systems, we are often baffled by their sudden transitions from simple to complex. Here I propose a solution to this conceptual problem. Given that emergence is often the result of many interactions occurring simultaneously in time and space, an ability to intuitively grasp it would require the ability to consciously think in parallel. A simple exercise is used to demonstrate that we do not possess this ability. Our surprise at the behaviour of cellular automata models, and the natural cases of pattern formation they mimic, is then explained from this perspective. This work suggests that the cognitive limitations of the mind can be as significant a barrier to scientific progress as the limitations of our senses.     

The ancient woodland concept as a practical conservation tool in Great Britain

In the 1980s the Nature Conservancy Council created an ancient woodland inventory showing all woods in Great Britain (GB) greater than 2 ha that were believed to have had woodland habitat cover continuously from 1600. Subsequently these lists have been maintained as three separate inventories by NCC's successors, English Nature (now Natural England), Countryside Council for Wales and Scottish Natural Heritage. This paper outlines the concept of ancient woodland as it has developed in GB, and how this idea gave rise to the ancient woodland inventories. The criteria used in compiling the inventories are discussed, including the inception dates and the threshold size, and the difference between ancient woodland and parkland. The inventories have been digitised for use with Geographic Information Systems (GIS), which has made them more accessible to planners and nature conservation bodies; however, the digitising process is more precise than the original definition of the boundaries of the ancient woodland. The three different countries have approached this issue slightly differently, taking account of the differing landscapes within which their ancient woodland exists. As the inventory developed, new legislation has also been brought into play to protect ancient woodland further. The inventory currently lacks detailed information concerning the condition or type of wood, beyond its semi-natural or plantation status. Ascertaining, and then maintaining, the condition of ancient woodland in Great Britain will be a major challenge for the future.     

Observations on the behavior of the Cerapachyine ants

Summary Notes on the predatory behavior of species ofCerapachys, Phyracaces, andSphinctomyrmex are given. All of the species thus far studied have proven to be myrmecophagous, feeding on the brood (and in some cases adults) of other species of ants. Raids are conducted by groups of workers and are usually of short duration. A foraging expedition ofPhyracaces cohici is described, during which the workers started out as a compact group but later dispersed into small groups and lone individuals deployed in a circular pattern around the home nest. On the basis of these observations there is suggested a hypothetical pattern of alternating foraging and raiding behavior, which is believed to result ultimately in an efficient exploitation by the ants of the surrounding territory. Notes on other phases of biology, including colony size and nest structure, are given.

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Résumé On a présenté quelques observations sur les habitudes de pillage des espècesCerapachys, Phyracases etSphinctomyrmex. Toutes les espèces étudiées jusqu'à présent sont myrmécophages; elles dévorent le couvain — et dans certains cas les adultes — d'autres espèces de Fourmis. Les incursions sont effectuées par des groupes d'ouvrières, et sont généralement de courte durée. On décrit une expédition de fourrage dePhyracaces cohici, au cours de laquelle les ouvrières, parties en troupe, se dispersèrent par petits groupes et en individus isolés déployés en cercle autour de leur fourmilière. Ces observations suggèrent l'existence d'un cycle alternatif de fourrage et de razzias, ce qui permettrait aux Fourmis l'exploitation efficace des territoires avoisinants. On décrit, de plus, quelques autres aspects de la biologie de ces espèces, notamment les dimensions et le plan de leurs fourmilières.