Reaction norm in response to temperature may change to adapt rapid brood development to boreal and subarctic climates in Myrmica ants (Hymenoptera: Formicidae)

Abstract

Abstract. Colonies of M. rubra, M. ruginodis and M. scabrinodis were collected in four geographic regions: Kiev, Ukraine (50.5°N, 30.5°E -first two species), Vladimir, Russia (56.2°N, 40.4°E -only last species), St. Petersburg, Russia (59.3°N, 30.3°E -all three species) and Chupa, Murmansk prov., Russia (66.3°N, 33.7°E -last two species). After artificial overwintering experimental cul tures consisting of 150 workers and one queen were established and kept at 16, 18, 20, 22, 24 and 26°C under long (22 h) day lengths. The workers reared eggs laid by queens into rapid (non-diapause) brood pupae and diapause larvae, which were removed and counted. The results showed the distinct latitudinal variation in the temperature effects on rapid brood rearing and in the thermal requirements for development. First, the period during which new rapid brood pupae appeared was found to be longer and the total number of pupae produced to be greater in ants from more southern populations. The number of diapause larvae reared by ant cul tures was also usually greater, in ants from southern sites. Second, low temperatures reduced the period of rapid brood production and the number of pupae reared to a greater degree in ants from northern populations. It means that northern Myrmica colonies rear rapid brood under lower temperatures evidently worse in comparison with ants from southern regions. Third, eggs and larvae from more northern sites appeared to develop faster than southern brood at temperatures above 16-18°C. This was because brood devel opment in northern populations was more temperature dependent, i.e. characterised by higher slopes of regression lines of develop ment rate on temperature. The sum of effective temperatures decreased with the advance to North. The higher slopes were always associated with higher thermal thresholds for development. We conclude that the reaction norm of Myrmica colonies, in response to temperature, changes according to the local climate in such a way that brood rearing, growth and development of individuals become more temperature dependent in more severe environments with colder and shorter summers. This lead to the increase of the physio logical and developmental responses at higher temperatures at the expense of a decrease within lower temperature range. In fact Myrmica colonies from northern populations need on average higher temperatures in their nests for successful production of new adults as compared to southern ants.

Physiological mechanism governing slow and fast development in predatory ladybirds

“…The inverse relationship between the sum of effective temperatures ( K ) and the lower temperature threshold for development ( td min ) has been reported previously (Honěk & Kocourek, 1988, 1990; Imura, 1990; Kiritani, 1991; Frazer & McGregor, 1992; Trudgill, 1995; Honěk, 1996a, b; Kipyatkov & Lopatina, 2002; Ikemoto, 2003). However, the finding that this relationship for aphidophagous and coccidophagous ladybirds differs significantly in elevation is novel.…”

“…Although the relative food quality of aphids and coccids may differ, the eggs of each species of ladybird are likely to be well provisioned with the nutrients necessary for embryonic development. Therefore, data from the literature on the rate of development of eggs of ladybirds at different temperatures were used to determine whether there is an inverse relationship between K and td min as recorded for other insects (Honěk & Kocourek, 1988, 1990; Imura, 1990; Kiritani, 1991; Frazer & McGregor, 1992; Trudgill, 1995; Honěk, 1996a, b; Kipyatkov & Lopatina, 2002; Ikemoto, 2003), and also whether the relationships for aphidophagous and coccidophagous ladybirds differ.…”

Comparative study of thermal reaction norms for development in ants

“…The geographic trends in intraspecific variation of thermal constants appear to be opposite to those in the interspecific variation that we observed. Our previous studies on adaptive latitudinal variation of the duration and thermal requirements for development in several Myrmica species (Kipyatkov & Lopatina , ; Lopatina et al . ) and Lasius niger (Kipyatkov et al .…”

“…Evidently, the strategy of concentrated brood‐rearing is only appropriate for temperate and boreal ants in combination with very fast brood development, allowing them to rear sexuals and new workers from eggs during a short warm season. In fact, Formica species have the shortest developmental times among temperate ants, their development is more temperature‐sensitive than those of the others, and these traits allow Formica workers to rear the brood much faster at higher temperatures (Kipyatkov & Lopatina ). According to our observations and published data, this strategy is characteristic of all genera of the Formicini tribe ( Alloformica , Cataglyphis , Formica , Proformica ) and of some species of the genera Dolichoderus , Pogonomyrmex , Ponera and Prenolepis (Kipyatkov ).…”

The ant (Hymenoptera: Formicidae) communities of the central interior of British Columbia: Adaptations to a temperature-constrained environment.

“…This same adaptation was also reported within a single species collected from different latitudes . The rate of larval development (Kipyatkov et al 2004;Kipyatkov and Lopatina 2002), as well as body and colony size, are also influenced by temperature (Kaspari 2005). …”