Trachypus taschenbergi Rubio-Espina, 1975

Pereira, Felipe Walter & Gonçalves, Rodrigo Barbosa, 2021, Behavior notes and prey spectrum of three species of the bee-hunting wasp Trachypus Klug (Hymenoptera: Apoidea), Papéis Avulsos de Zoologia 61, pp. 1-7 : 3-4

Trachypus taschenbergi Rubio-Espina, 1975

Trachypus taschenbergi was the more abundant and spread species in the study area. We found a total of 87 nests distributed in 18 divisions: 68 (n = 2); 71 (n = 1); 86 (n = 8); 87 (n = 13); 88 (n = 7); 89 (n = 1); 90 (n = 2); 91 (n = 3); 92 (n = 24); 94 (n = 4); 160 (n = 5); 197 (n = 2); 198 (n = 3); 211 (n = 1); 212 (n = 2); 262 (n = 3); 416 (n = 3); 452 (n = 4). In divisions 68 and 71 the nests were predominantly covered by shadows from trees above the earth bank, but exposed to sunlight in early afternoon (around 12 noon to 2 PM). Those in divisions 86 - 88 were located in a part of the earth banks predominantly exposed to sunlight throughout the day and with a portion partially covered by the shade from a bus stop in the afternoon. Nests in 89 - 94, 160, 211 and 212 were exposed to sun throughout the day, while in 197, 198, 262, 416 and 452 were constantly in the shade.

Females were active during the entire year, including the winter season, we observed few females excavating nests in June 2018 (n = 5) and in August 2018 (n = 3). Activity was not detected in May 2019, a very rainy month, but in June 2019 a few females were observed. Circular statistics revealed a non-uniformly abundance distribution along the year and a significant seasonal pattern (n = 395 observations; p <0.05, Rayleigh (Z) test) was found with the mean vector in November ( Table 1; Fig. 2B ). Males were observed from September to March. They were more abundant on October and January (spring and summer).

The foraging activities started after 9 AM, usually with females opening the nests between 9h30 AM and 10h30 AM. As in T. elongatus , nest construction and provisioning rarely continued until after 2 PM. Females exhibited guarding behavior, very similarly to T. elongatus , by exposing its head and opening its mandible when another individual tried to enter in its nest.A marked female was observed entering nests and in one case, the female stayed a few minutes inside a nest and then was expelled by a resident female. Later, the same marked female entered another burrow and stayed inside, expelling other females that tried to enter. No evidence of two or more females sharing the same nest was observed. Activity of males near to the nesting sites occurred in the afternoon, when the females were guarding the nests. The males flew in aggregations of 10 - 20 individuals, in which one at time tried to enter a nest, while the females expelled the male by exposing its head and opening its mandible. After a while (about 30 minutes) the female allows one male to enter the nest and keep protecting the entrance. Presumably,copulation occurred inside the nest, no mating was observed near the nesting sites.

Provisioning activities were detected from September to April. The observed prey spectrum showed a strong preference for drones of Paratrigona subnuda Moure, 1947 , only one worker was recorded (n = 59 preys). The foraging trips usually took less than five minutes of duration. We observed a female exiting the nest and returning in less than two minutes with a prey and three minutes later she left the nest again. A marked female provisioned her nest four times in a period of 15 minutes. On the other hand, we observed a foraging trip that last- ed 30 minutes. Whenever arriving carrying a prey, a female spent time flying over the nesting area, looking for its nest, and landed near the entrance ( Fig. 3A ) entering quickly.When a female carrying a prey was prevented by us from entering the nest (with a stick or the insect net), she immediately dropped and abandoned the prey, returning a few minutes later with a new prey.

Figures

Figure 2.Rose diagrams forseasonal activities of (A) Trachypus elongatusand (B) Trachypus taschenbergi,consideringthe number of female observations per day of fieldwork.Months are treated as sectors of 30 degrees each,with January corresponding to 0 and December to 330.

Figure 3. Trachypus taschenbergi biology.(A) female carrying aprey (Paratrigonasubnuda drone) nearthe nestentrance.(B)female exiting the nest;(C-E) afemale trying to enter an occupied nest and being expelled bya female that was inside the nest.