Some ethological aspects of the trophobiotic interrelations between ants (Hymenoptera: Formicidae) and larvae of the sawfly Blasticotoma filiceti (Hymenoptera: Blasticotomidae)

Abstract

Abstract. Some ethological aspects of the interrelations between ants and the larvae of Blasticotoma filiceti Klug, 1834 were investigated in the Altai Republic and Novosibirsk Region in [2006][2007][2008]. The interactions of ants with the larvae of this sawfly are determined by the concealed way of life style of B. filiceti. The majority of the ant-sawfly encounters occurred near holes in fern fronds at the moment when larvae excreted liquid or left their tunnels before descending to the soil prior to overwintering. Sawfly larvae visited by more aggressive ants, such as Formica s. str., leave the fern fronds slowly, which enables them to avoid inciting attacks by ants. The behaviour of the ants while collecting the larval excretion is similar to their behaviour at sugar troughs. The organisation of the collecting larval excreta by ants was investigated in detail in the cases of Formica polyctena Förster, 1850 and Myrmica rubra Linnaeus, 1758. The individual fern plants with sawfly larvae are attended by relatively constant groups of foragers in both cases. However, the highly social red wood ants interact with sawfly larvae in a more complex way. While the working groups of M. rubra tending sawfly larvae consist only of non-aggressive "unspecialized" foragers, those of F. polyctena include also a few "on duty" ants that protect the trophobionts, at least from the other ants.

The ghost of the Cretaceous terrestrial revolution in the evolution of fern–sawfly associations

“…As well as the two exclusively pteridophagous families Blasticotomidae and Heptamelidae, several sawfly genera in the Tenthredinidae and Pergidae include pteridophagous species (Togashi, 1989;Smith et al, 2002;Vikberg & Liston, 2009;Macek, 2010;Taeger, 2013;Isaka & Sato, 2014a, 2014b. Some pteridophagous sawflies show traits that are less widespread, such as the spore-feeding of Rocalia (Sawamura et al, 2009), the complex manipulation of the fern hosts during oviposition by Pseudoheptamelus (Vikberg & Liston, 2009), and the specialized interaction of the fern-miner Blasticotoma filiceti Klug with ants (Shcherbakov, 2006;Novgorodova & Biryukova, 2011).…”