Arachnologische Mitteilungen 57

34 M. Suvák Additional observations were made on several other in- dividuals of Parasteatoda and Uloborus plumipes to assess their responses when disposable myrmecochorous diaspores were thrown directly into their webs. Additional tests offering seeds of Costus dubius as poten- tial food were conducted with Pholcus sp. (Pholcidae), Agelena labyrinthica (Clerck, 1757) (Agelenidae), Hasarius adansoni (Audouin, 1826) (Salticidae) and Mangora acalypha (Walcke- naer, 1802) (Araneidae). Results Parasteatoda (Theridiidae) can actively collect myrmecochorous diaspores ( Costus dubius ) in the vicinity of their webs Some seeds of C. dubius were pulled up from the sill by spi- ders and other seeds were thrown out from the web (Fig. 1). Usually the picked up seeds remained in the web long enough for counting once a day. A possible source of error could be ants carrying the seeds away from below the spiders. Never- theless, the results show the ability of Parasteatoda sp. spi- ders to find the seeds in the vicinity of their webs, pull them up and consume them (Fig. 2). In the humid conditions of greenhouses, the attractive properties of the selected seeds with their elaiosomes were preserved for at least three weeks after their separation from mother plants (Fig. 1). Selected myrmecochorous diaspores placed directly into the webs of Parasteatoda sp. and Uloborus plumipes were consumed in most cases Myrmecochorous diaspores from different plants were placed into the webs of five Parasteatoda sp. (1× C. dubius , 1× G. ni- valis , 2× H. nobilis and 1× C. majus ) and 24 U. plumipes (3× A. europaeum , 4× C. dubius , 5× C. solida , 1× G. nivalis , 4× H. no- bilis and 7× C. majus ). Times between putting a seed into the web and the approach of a spider to the potential food source varied. Especially in the case of U. plumipes a seed may not be touched for several hours. However, sooner or later, the dias- pores of all tested myrmecochorous plants were eaten (Fig. 3, 4). Only one subadult female of U. plumipes threw out three seeds of C. majus from its web shortly after finding them, pro- bably without initial feeding. In all other cases seed eating took minutes to hours. Sometimes seeds were first wrapped with silk (Fig. 4c) just like in real prey capture. Tests with other spider species Some other, less common spider species were also offered seeds of C. dubius as potential food.These additional tests in- cluded the following spider species: Pholcus sp. (n = 5), Man- gora acalypha (n = 1), Agelena labyrinthica (n = 1) and Hasari- us adansoni (n = 3). None of the tested spiders was observed feeding on seeds. However, when three seeds were put into Fig. 4: Different individuals of Ulo- borus plumipes with diaspores of: a. Asarum europaeum ; b. Corydalis solida ; c. Costus dubius ; d. Galan- thus nivalis ; e. Hepatica nobilis ; f. Chelidoniummajus