The shoemaker’s son always goes barefoot: intercontinental dispersal of Ostracoda (Crustacea) by scientists attending an IBS excursion

Abstract

correspondence ISSN 1948-6596 The shoemaker’s son always goes barefoot: intercontinental dis- persal of Ostracoda (Crustacea) by scientists attending an IBS excursion Human activity is one of the main mechanisms through which alien species are dispersed, often unintentionally. Freshwater alien species com- monly are transported between continents by vectors such as ballast water or ship transport of commercial stocks for aquaculture or agriculture (Amat et al. 2005, Escriva et al. 2012, Strayer 2010). Recent studies conducted within the same biogeographic region on plant seed and aquatic invertebrate dispersal have shown that shoes, clothes and car wheels also can be important vec- tors (Lonsdale and Lane 1994, Mount and Pickering 2009, Waterkeyn et al. 2010, Wichmann et al. 2009). Many scientists participate regularly in re- search meetings held in continents other than where they work, and these usually include excur- sions to natural areas. When the meeting is over and they return to their home region, the partici- pants could act as vectors for long-distance dis- persal (LDD). Here, we checked the dispersal po- tential of freshwater invertebrates through trans- continental traveling of practicing scientists at- tending an International Biogeography Society meeting. The International Biogeography Society (IBS) organized its 6 th Biennial Conference in Mi- ami (Florida) in January 2013. Three researchers of the University of Valencia enrolled in fieldtrips to the Everglades on the 9 th and to the Faka- hatchee Strand on the 13 th , organized as part of the meeting (Hortal et al. 2012). Both trips in- volved swamp tromp activities, where the atten- dants enjoyed walking in the shallow (c. 15–50 cm deep) wet prairies, sloughs and cypress swamps for several hours using their own footwear, which got wet and muddy. Upon arrival to the hotel one pair of hiking trainers was washed in tap water, (sample A) while two pairs of hiking boots (samples B and C) were kept dirty. Each pair, after being air-dried, was stored in a different plastic bag until arrival to the city of Valencia (Spain) the 16 th of January. Researchers returned home by plane with the boots in their luggage. In the laboratory, the three pairs of foot- wear were individually washed with de-ionized water in a plastic container on the 21 st of January. Each wash sample (A, B and C) was homogenized and separated in three subsamples accounting for a total of nine 1-liter aquaria. All aquaria were placed in a culture chamber at a temperature of 15 oC and 16 hours light : 8 hours dark photope- riod. Water levels were kept constant throughout the study by adding distilled water when required. During the 28 day experimental period each aquarium was checked for invertebrates on seven occasions (on days 1, 3, 7, 12, 16, 22 and 28). Lim- nological parameters were recorded on day 12. Each check consisted of filtering the water from each aquarium through a 100 µm mesh net and observing the retained material under a stereomi- croscope (10–100x magnification). The inverte- brates found (belonging to Ostracoda) were pre- served in 70% ethanol. Ostracod specimens were identified according to Furtos (1936), Keyser (1977) and Teeter (1980). The electrical conductivity (EC = 1.5 ± 0.4 mS/cm), water temperature (T = 17.3 ± 0.5 oC) and pH (pH = 8.3 ± 0.05) in the cultures did not vary notably among aquaria. On day 12, one living ostracod and one right valve of the same species were collected from aquarium B2, all identified as females of Candona furtosae Teeter, 1980 (Fig. 1), a species only recorded previously in Florida (USA). The carapace lengths of these individuals measured 1.05 and 1.10 mm, similar to measures of adult females collected in Pleistocene sedi- ments of Florida by Teeter (1980). This author re- marks that C. furtosae was also found in wayside pools by Furtos (1936) and mangrove regions of the Everglades National Park (Keyser 1977) in Southern Florida (in both publications misidenti- fied as C. balatonica). Karanovic (2006) checked the material of Furtos (1936) and reassigned her frontiers of biogeography 6.2, 2014 — © 2014 the authors; journal compilation © 2014 The International Biogeography Society