The cavity-nest ant Temnothorax crassispinus prefers larger nests

Abstract

Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm 3 , respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm 3 nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

Size-related mortality during overwintering in cavity-nesting ant colonies (Hymenoptera: Formicidae)

“…The artifi cial sites used in the experiment, which were in birch woodblocks, were readily accepted by Temnothorax ants (cf. Foitzik et al, 2003;Mitrus, 2015b). However, colonies abandoned three nests in this experiment, which indicates that ants may prefer different cavities or a different localities.…”

Impact of plant cover on the cavity‐nesting ant Temnothorax crassispinus

“…Generally, per‐capita productivity declines in larger ant colonies (Kramer et al ., ), but the ant T. crassispinus did not show a decrease in per‐capita productivity with increasing colony size (Kramer et al ., ). Mitrus () showed in a laboratory experiment that per‐capita productivity of sexual individuals only was positively correlated with the number of workers, but only for colonies from bigger chambers (860 mm 3 ). For colonies reared in nest sites with cavity volume of 470 mm 3 , there was no such correlation.…”

“…For colonies reared in nest sites with cavity volume of 470 mm 3 , there was no such correlation. It was found in our experiment that colonies from patches of balsams had higher per‐capita productivity (cavity volume of nest sites was 780 mm 3 ; like Mitrus (), we analysed the production of sexual individuals only, and we have no data on production of new workers). The nest sites in balsams, or just whole areas, were considered by ants to be worse (see above).…”

“…780 mm 3 , calculating the reduction in the length of the drilled cavity due to the beech plugs inserted in the hole. Such nest chambers made in wood pieces are willingly accepted by Temnothorax ants (Foitzik et al ., ; Mitrus, ).…”

“…Each woodblock was drilled lengthwise to form a 4 mm hole, which was tightly closed on one side with a beech plug, and partially closed by a splinter from such a plug on the other side; the final cavity volume of such a nest was c. 780 mm 3 , calculating the reduction in the length of the drilled cavity due to the beech plugs inserted in the hole. Such nest chambers made in wood pieces are willingly accepted by Temnothorax ants (Foitzik et al, 2003;Mitrus, 2015).…”