E J Godzinska

The effects of age and past and present behavioral specialization on behavior of workers of the red wood ant Formica polyctena Först. during nestmate reunion tests

Social insect workers usually participate first in intranidal tasks and then switch to extranidal ones. However, foragers may switch again to intranidal brood care. This process is called the behavioral reversion. We applied dyadic nestmate reunion tests to explore behavioral differences between five groups of workers of the red wood ant Formica polyctena: callows (newly eclosed workers), nurses, reverted nurses (foragers that switched back to intranidal brood care in response to exposure to brood in absence of nurses), and two groups of foragers. Inter-group differences between the tested ants were related both to age and past and present behavioral specialization. Callows were the least active and their behavior was characterized by the lowest tempo. Nurses usually behaved in a way intermediate in respect to behavior of callows and the ants that had already passed the transition to extranidal tasks. The behavior of reverted nurses showed both similarities and differences with respect to behavior of foragers. Some traits of behavior of reverted nurses were similar as in the case of nurses, or intermediate in respect to both nurses and foragers. Behavioral reversion of workers of F. polyctena has thus other behavioral correlates besides the reappearance of intranidal brood care.

Ant predation on Colorado beetle (Leptinotarsa decemlineata Say)

The interactions between the ants and the Colorado beetles (Leptinotarsa decemlineata Say) were observed in 7 nests of Formica polyctena Först, and in one nest each of F. pratensis Retz., F. rufa L. and F. rufibarbis F. The research was carried out at four sites in central‐eastern Poland in the years 1984–1985. The evidence for interactions between the ants and the Colorado beetles is based on observations of ants attacking and dragging adult Colorado beetles (in 4 nests of F. polyctena and one nest of F. rufa), carrying their remnants (in 4 nests of F. polyctena), and dragging L3 and L4 larvae of that species (in one nest of F. pratensis). Numerous remnants of adult Colorado beetles were also found on the dumping grounds of 5 nests of F. polyctena and of one nest off. rufibarbis.

Brain GABA and glutamate levels in workers of two ant species (Hymenoptera: Formicidae): interspecific differences and effects of queen presence/absence.

Presence of amino acid neurotransmitters gamma‐aminobutyric acid (GABA) and glutamate (Glu) in ant brains was reported in very few studies. To learn more about factors influencing GABA and Glu levels in ant brains, we applied high‐performance liquid chromatography to measure levels of these compounds in single brains of workers of 2 ant species, Myrmica ruginodis (subfamily Myrmicinae) and Formica polyctena (subfamily Formicinae) taken from queenright/queenless colony fragments and tested in dyadic aggression tests consisting of an encounter with a nestmate, an alien conspecific or a small cricket. Brain glutamate levels were higher than those of GABA in both tested species. Brain GABA levels (in μmol/brain) and GABA : Glu ratio were higher in M. ruginodis (a submissive species) than in F. polyctena (a dominant, aggressive species) in spite of smaller brain weight of M. ruginodis. Brain glutamate levels (in μmol/brain) did not differ between the tested species, which implies that glutamate concentration (in μmol/mg of brain tissue) was higher in M. ruginodis. Queen absence was associated with increased worker brain GABA levels in F. polyctena, but not in M. ruginodis. No significant effects of opponent type were discovered. As GABA agonists enhance friendly social behavior in rodents, we hypothesize that elevated brain GABA levels of orphaned workers of F. polyctena facilitate the adoption of a new queen. This is the first report providing information on GABA and glutamate levels in single ant brains and documenting the effects of queen presence/absence on brain levels of amino acid neurotransmitters in workers of social Hymenoptera.

Identification of putative volatile sex pheromones in female domestic dogs (Canis familiaris)

More than hundred urine samples, vaginal secretions, vulval and anal imprints as well as anal sac secretions, collected during various phases of the ovarian cycle, were evaluated with the HS-SPME/GC-MS technique. The results indicate there were differences among samples of urine collected during particular phases of the ovarian cycle. Unequivocally, the amount of carbonyl aromatic compounds, such as acetophenone (hypnone) and benzaldehyde, increased during the period of proestrus and estrus of the estrous cycle. This was accompanied by increases in methylketones, e.g., 2-octanone, 2-pentanone and 3-hexanone. Simultaneously, amounts of sulfide compounds (1-methylotiopropane; 1-methylotiobutane, 1-methylotipentane and dimethyl trisulfide) decreased during the period of estrus and abruptly increased in diestrus. These observations suggest a possible dual mechanism of interaction between males and females during and subsequent to the mating period, including the existence of both attracting and repelling signals. No significant changes were detected in samples other than urine. Further studies including a proteomic approach as well as behavioral assessments are suggested to identify the complete range of estrual semiochemical signals and to verify the semiochemical activities of identified substances.

Increased Risk Proneness or Social Withdrawal? The Effects of Shortened Life Expectancy on the Expression of Rescue Behavior in Workers of the ant Formica cinerea (Hymenoptera: Formicidae)

In social insects behavioral consequences of shortened life expectancy include, among others, increased risk proneness and social withdrawal. We investigated the impact of experimental shortening of life expectancy of foragers of the ant Formica cinerea achieved by their exposure to carbon dioxide on the expression of rescue behavior, risky pro-social behavior, tested by means of two bioassays during which a single worker (rescuer) was confronted with a nestmate (victim) attacked by a predator (antlion larva capture bioassay) or immobilized by an artificial snare (entrapment bioassay). Efficacy of carbon dioxide poisoning in shortening life expectancy was confirmed by the analysis of ant mortality. Rescue behavior observed during behavioral tests involved digging around the victim, transport of the sand covering the victim, pulling the limbs/antennae/mandibles of the victim, direct attack on the antlion (in antlion larva capture tests), and snare biting (in entrapment tests). The rate of occurrence of rescue behavior was lower in ants with shortened life expectancy, but that effect was significant only in the case of the entrapment bioassay. Similarly, only in the case of the entrapment bioassay ants with shortened life expectancy displayed rescue behavior after a longer latency and devoted less time to that behavior than ants from the control groups. Our results demonstrated that in ant workers shortened life expectancy may lead to reduced propensity for rescue behavior, most probably as an element of the social withdrawal syndrome that had already been described in several studies on behavior of moribund ants and honeybees.

Human and ant social behavior should be compared in a very careful way to draw valid parallels

Gowdy & Krall provide an interesting discussion of evolutionary origins and consequences of ultrasociality. However, some of their statements concerning various features of ant and human social behavior do not adequately reflect present knowledge about the discussed issues, which include, among others, polyethism, cultural information transfer, within-group conflicts and resistance in ant societies, and reproductive division of labor in humans. Gowdy & Krall (G&K) provide an interesting discussion of evolutionary origins and consequences of ultrasociality, an advanced form of social behavior that evolved independently in both social insects and humans. Their reflections are thought-provoking, but some statements concerning various features of ant and human social behavior do not reflect adequately the present knowledge about the discussed issues.

Capturing the essence of decision making should not be oversimplified.

Bentley et al. propose a thought-provoking approach to the question of causal factors underlying human choice behavior. Their map model is interesting, but too simplified to capture the essence of decision making. They disregard, among other matters, qualitative differences between various subcategories of social influences, and the role of neurobiological factors engaged in interdependent individual and social decision-making processes.