Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 52. (Budapest 1960)

Móczár, L.: The loess wall of Tihany and the nesting of Odynerus spiricornis Spin. (Hymenoptera, Eumenidae)

as their flying speed diminished in front of the loess wall, they often fell down together with their load. The weighty sawfly larve had obviously brought them down. When they alighted on something, they tried to take to wings again. At other times, they climbed up the steep wall. It also happened that they flew to the nearby shrubs or onto some projection of the wall, warming themselves for some moments (Plate IV, fig. 11), wrinkling their wings, and then flying off again, still tightly clasping the sawfly larve with their fore and middle legs. They carried the sawfly larvae mainly between, lft: 1 I : 25 on 21 July, in spite of the fact that the hottest period was between 13 : 30—16 : 30 (40—43° C). Odynerus Nr. 17. was carrving already the second day the sawfly larvae into its turret on 22 July." Nine wasps were carrying sawfly larvae between 10 : 23—13 : 51 on 23 July ; the temperature was 23,5° C, the hottest (43—44° C) between 15 : 30—17 : 30. One of the wasps carried the sawfly larve, contrary to the customary way (Plate III, fig. 7), grasped at the end of its abdomen and not at its throat, at 11 : 20. Another wasp brought sawfly larvae into its turret at 12 : 24, 13 : 02, and 13 : 36. leaving its burrow in 25", 22", 18*. The traffic in sawfly larvae was the highest around noon on 24 July, at a temperature of 34° C, though later (between 14 : 00—15 : 30) it rose to 47° C. At 10 : 52, a wasp, soon after disappearing in the turret, emerged shortly again in the entrance, dragging the sawfly larva and flying away with it. Did it stray into an alien nest? In spite of the hot, sunny day of 30 Julv, there was onlv one wasp carrying its prey at 12 : 05. We may safely conclude from what was said above that the wasps do not carrv the sawfly larvae provisions in the hottest hours of the day. During flight, they hold, that is, grasp the sawfly larve with their mandibles and legs to their bodies (Plate III, fig. 7). The long abdominal end of the sawfly larve will hang out, even so, from below the abdomen of the wasp. When alighting on the turret, thev cling to it first by their anterior and then by their posterior legs (Plate III, fig. 8—9), holding the sawfly larve with their mandibles and middle legs. On and within the turret, they hold it only by their mandibles. According to literature data (G i r a u d 1863, Chrétien 1896), Odynerus spiricornis Spin, carries the larve of the sawfly Lyda inanita into its nest. I never met with this species during my observations ; the wasps were carrying the green larvae of Neurotoma nemoralis L. and the yellow larvae of JV. flaviventris Retz. (E n s 1 i n 1914). The green one was the more frequent, the yellow more seldom. The two Neurotoma species live, frequently in masses, in a loose web on various kinds of (also cultivated) plants, mainly on Pomaceae, Pirus communis, Crataegus, Mespilus, Cotoneaster and Prunus, appearing sometimes as a pest. The damages of the sawfly larvae occur in May and June in Germany (E n s 1 i n 1914). This is the cause why the highly host-specialized Odynerus spiricornis Spin, is no more active in August. The sealing-up of the cells Odynerus Nr. 2. It arrived at its nest at 10 : 18 on 21 July. It flew away at 10 : 21 to a distance of 2 and a half meters, where it gnawed out a mud pill, hurrying back with it into its nest in a minute. The same scene occurred again at 10 : 31. It was discovered only at the breaking up of the nest that it must have transported these pills for making the stoppers sealing up the cell, since their color was somewhat darker than that of the cell.