The pheromonal activity of chiral 3-octanol for Myrmica ants

ABSTRACT. The (R)-(-)-3-octanol from the mandibular glands of Myrmica ants is the only enantiomer active as an attractant pheromone for M.scabrinodis Nyl. The S enantiomer is inactive and its presence decreases slightly the response of M.scabrinodis to the R enantiomer. (R) and (S)-2-octanol are inactive.     

Respiration in the larvae of the ants Myrmica scabrinodis and Lasius flavus

ABSTRACT. Respiratory rates of larvae of Myrmica scabrinodis Nyl. and Lasius flavus Fab. were measured at 5, 15 and 25°C using the micro-Warburg technique. Larvae collected in the winter and spring were a mixture of all three castes. In the summer collection it was possible to separate the gyne-potential larvae from the others by virtue of their greater size. The respiration of the larvae of both species showed a decreasing response to temperature as they developed. The winter larvae of L. flavus could be categorized into two groups on the basis of the proportions of dry matter. They were also significantly different in their weight-specific respiratory rate, and their response to temperature changes. Gyne larvae were about 7 times as heavy as the others, but their weight-specific respiratory rate was the same as in the other larvae in M. scabrinodis and actually higher in L. flavus. The highest respiratory rates occurred when the dry matter content of the larvae was lowest, in the summer collection for M. scabrinodis and the spring collection for L. flavus.     

Mandibular gland secretions of workers of Myrmica rugulosa and M.schencki: comparison with four other Myrmica species

ABSTRACT. The mandibular glands of the two species of ant, Myrmica schencki Em. and Myrmica rugulosa Nyl., contain mixtures of similar compounds, but in different proportions. M.rugulosa produces 3-pentanol, 3-hexanone, 3-hexanol, 3-heptanone, 3-heptanol, 3-octanone (by far the most abundant component), 3-octanol, 3-nonanol, 3-decanone and 6-methyl-3-octanone, in addition to small amounts of ethanal, acetone and methylpropanal. M.schencki produces most of these (though much less 3-octanone and much more 3-octanol), but also produces significant amounts of 3-nonanol, 3-decanol and 6-methyl-3-octanol, while producing no detectable 3-pentanol or 3-hexanone. The mandibular gland secretions of these two species attract the workers, increase their linear speed, and reduce their sinuosity of movement. In M.schencki these behavioural activities are caused by 3-octanol and 3-octanone, the effect of a synthetic mixture of the two being exactly like that of an isolated mandibular gland; the two compounds act together to cause attraction and increase linear speed, and in synergy to reduce the workers' sinuosity of movement. In M.rugulosa , 3-octanol, 3-octanone and 6-methyl-3-octanone are the major active constituents. 3-Octanone attracts the workers, its effect being enhanced by 3-octanol; it also increases the ants' linear speed, this effect being moderated slightly by the 3-octanol. Presented together these two substances act synergistically to decrease the workers' sinuosity of movement, and reproduce exactly the overall behavioural activity of an isolated mandibular gland. The chemical and behavioural results are combined with those previously reported to explain the responses of M.rubra, M.ruginodis, M.rugulosa, M.sabuleti, M.schencki and M.scabrinodis workers to isolated mandibular glands of these species.     

The importance of daylength and queens for larval care by young workers of the ant Myrmica rubra L.

ABSTRACT. Workers whilst still less than a month from emergence rear early stage larvae better in a 16h day than in one of 14h. The callows must perceive the diel rhythm directly because there are no foragers to give them a clue, and the larvae are kept in the dark and cannot respond directly. This, and the study of egg-laying by young workers that preceded it, indicates that the extra hours daylight enable the workers to avoid the reproductive diapause that normally prepares them for hibernation. They retain active ovaries, ingest and share food with larvae either as trophic eggs or as a regurgitate from the crop.
In late summer, callows can rear sexual larvae in spring condition. Queens have a small negative effect on this, expressed as a smaller, though still gyne, pupa produced a little earlier. This weak response to queens develops into a strong negative one at a constant temperature of either 10 or 20°C. The workers then behave as they normally do in spring, and feed a watery regurgitate (dietary control) or, if this fails to arrest sexual development, physically harass the larvae by biting them in the ventral thorax (manipulative control). Large workers then result instead of gynes.     

A critical review of the discovery and application of a migratory pheromone in an invasive fish, the sea lamprey Petromyzon marinus L.

The sea lamprey Petromyzon marinus , an ancient and parasitic agnathan fish native to the North Atlantic, invaded the Laurentian Great Lakes approximately a century ago triggering its fisheries to collapse. Presently, this species is held in check through a toxicant-based control programme directed by a bi-national treaty organization that seeks to develop a more broadly based integrated pest management (IPM) strategy. After a long and difficult search, the most active components of a migratory pheromone for the sea lamprey were identified and synthesized. This pheromone has remarkable potency and considerable potential to enhance various control strategies that fall within an IPM scheme. The pheromone is comprised of a mixture of at least three sulphated steroids: petromyzonamine disulphate (PADS), petromyzosterol disulphate (PSDS) and petromyzonol sulphate (PS). A steroidal sex pheromone appears to have similar promise. These discoveries, which are prompting development of the first pheromonally guided pest management programme for an invasive fish, have revealed significant scientific and policy challenges. Among the former are the needs to acquire long-term and significant support for the science, to synthesize sufficient quantities of cues, and to deploy and measure pheromonal components in natural waters. Among the latter are the needs to regulate this new type of 'pesticide', protect these technologies from exploitation and promote future research on this and other invasive fish species. Lessons from these experiences may be applicable to the study of other invasive fishes.     

Slow loss of deoxyribose from the N7deoxyguanosine adducts of estradiol-3,4-quinone and hexestrol-3',4'-quinone. Implications for mutagenic activity

A variety of evidence has been obtained that estrogens are weak tumor initiators. A major step in the multi-stage process leading to tumor initiation involves metabolic formation of 4-catechol estrogens from estradiol (E2) and/or estrone and further oxidation of the catechol estrogens to the corresponding catechol estrogen quinones. The electrophilic catechol quinones react with DNA mostly at the N-3 of adenine (Ade) and N-7 of guanine (Gua) by 1,4-Michael addition to form depurinating adducts. The N3Ade adducts depurinate instantaneously, whereas the N7Gua adducts depurinate with a half-life of several hours. Only the apurinic sites generated in the DNA by the rapidly depurinating N3Ade adducts appear to produce mutations by error-prone repair. Analogously to the catechol estrogen-3,4-quinones, the synthetic nonsteroidal estrogen hexestrol-3',4'-quinone (HES-3',4'-Q) reacts with DNA at the N-3 of Ade and N-7 of Gua to form depurinating adducts. We report here an additional similarity between the natural estrogen E2 and the synthetic estrogen HES, namely, the slow loss of deoxyribose from the N7deoxyguanosine (N7dG) adducts formed by reaction of E2-3,4-Q or HES-3',4'-Q with dG. The half-life of the loss of deoxyribose from the N7dG adducts to form the corresponding 4-OHE2-1-N7Gua and 3'-OH-HES-6'-N7Gua is 6 or 8 h, respectively. The slow cleavage of this glycosyl bond in DNA seems to limit the ability of these adducts to induce mutations.