Effect of Starvation on the Feeding Activity Toward Sugary Food in the Ant Tapinoma nigerrimum (Nylander, 1856)

In this study, we investigated the effect of starvation on the feeding behavior of the ant Tapinoma nigerrimum. In particular, we tested the response of ants that had experienced different levels of starvation, toward sucrose solutions of increasing concentration. As expected, starved ants promptly reacted to the sugary food sources with a higher rate of acceptance as compared to satiated ones. Acceptance increased both with sugar concentration and the length of the starvation period. However, a consistent fraction of the starved ants did not feed on the solutions, suggesting that starvation had different effects on different individuals, even though they all had food ad libitum before the beginning of the tests, had comparable body sizes, and were collected from the same trail. The different acceptance of sugary solutions may be, therefore, merely because ants fed on the experimental food at different times. Interestingly, in all the experimental groups, ants appeared to satiate quickly, irrespective of the solution tested and fasting duration. This would suggest that the rate of ingestion was independent of these factors, a result partially at odds with previous studies. This study is one of the few ones dealing with the behavioral response of an ant species to a famine event

The Effect of the Introduced Red Wood Ant Formica paralugubris on the Frequency of Ant Nests and First Plesiobiotic Association between Myrmica ruginodis (Nylander, 1846) and Lasius flavus (Fabricius, 1782)

Red wood ants are ecologically dominant species that affect the composition of the invertebrate community. In the past century, one of these species, Formica paralugubris (Seifert 1996), was introduced outside its native area (the Alps), in the Apennines (Italy). Here we investigated the effect of the presence of an introduced population of F. paralugubris on the frequency of nests of other ant species in Abetone, Central Apennines. Ant nests were found only in the area unoccupied by F. paralugubris. In this area, we also found one pleometrotic association between queens of Lasius flavus (Fabricius, 1782) and two plesiobiotic associations, one between Formica fusca (Linnaeus, 1758) and L. flavus and the other one between Myrmica ruginodis (Nylander, 1846) and L. flavus. This latter is the first plesiobiotic relationship reported between these two species, the second reported for M. ruginodis and the 10th for L. flavus. Additionally, this is the first plesiobiotic association reported for the Mediterranean region and Southern Europe

Zero-Knowledge Proofs from the Action Subgraph

In this work, we investigate techniques to amplify the soundness of zero-knowledge proofs of knowledge for cryptographic group actions. We explore the use of a particular graph generated from the group action of random element and provide a fully general protocol with only minimal assumptions on the group action properties. This technique can be seen also as generalization of MPC-in-the-head approach for the context of (non-abelian) group actions. We show that a straightforward translation of the paradigm is unlikely to provide a practical improvement over the simpler construction of a 3-pass Sigma protocol. We then describe a novel approach and show that it yields a computational advantage, therefore laying the ground for new, efficient protocols

Sub-lethal doses of imidacloprid alter food selection in the invasive garden ant Lasius neglectus

Despite several restrictions to their use, neonicotinoid insecticides are still widely employed worldwide. Residual sub-lethal amounts of these chemicals can have detrimental effects on the behavior of non-target insects. Toxic effects on economically important species such as bees have been widely documented, but less is known about their toxic action on other social insects, such as ants. In this study, we assessed the effect of different sub-lethal doses of the neonicotinoid imidacloprid on the ability of colonies of the invasive ant Lasius neglectus to select the most profitable resource. We used Y-shaped mazes having an imidacloprid-polluted or an unpolluted sucrose solution on the two branches. Two sucrose (0.1 M, 0.5 M) and two imidacloprid (1 μg/ml, 10 μg/ml) concentrations were used. In parallel, we evaluated the marking activity of foragers who fed on the same solutions. We found that the 0.1 M sugar solution polluted with 1 μg/ml imidacloprid was significantly more frequently selected in binary choices experiments than the unpolluted resource. Moreover, the ingestion of the same combination of sugar and imidacloprid significantly increased the marking rate of foragers. The higher concentration of the pollutant had lower effects, probably because of the hormesis phenomenon. Results suggest that the lower sub-lethal dose of imidacloprid can lead ants to select again the polluted resource. This “active” selection of the pollutant may magnify the negative effects on the colonies. Due to their ecological role, any impairment of ant survival or behavior may have detrimental cascade effects on the whole ecosystem.info:eu-repo/semantics/publishedVersio

Spatial variation of the aggressive response towards conspecifics in the ant Crematogaster scutellaris (Hymenoptera Formicidae)

In this study we investigated the relationship between spatial distance and intraspecific aggression in the Mediterranean tree-nesting ant Crematogaster scutellaris. Aggression tests were carried out in the field confronting group of workers (20 from each nest) collected from pairs of nests located at increasing distances one from the other (5, 10, 20, 40 and 80 meters). For each distance, 6 replicate tests, using different pairs of nests, were carried out. The probability of aggression and the time of the first aggressive event were recorded and modelled as a function of the distance between two nests using generalised linear models. Results showed that both the probability of aggression and the time of first attack were correlated to spatial distance in a complex way, having their maximum at intermediate distances between nests. The observed relationship cannot be simply interpreted according to the “dear enemy” or the “nasty neighbour” effects and contains elements in favour of both