nigrolineata, Micronecta scholtzi, Ranatra linearis, Notonecta meridionalis and Hebrus pusillus) . Previous ..... Notonecta maculata Fabricius, 1794. Mallorca: ...
209
Hydrobiologia 324 : 209-217, 1996 . © 1996 Kluwer Academic Publishers . Printed in Belgium .
Distribution and associations of the aquatic Heteroptera of the Balearic Islands (Spain) J. Garcia-Aviles l , M. A. Puig 2
& A. G. Soler 3 1 Centro de Investigacidn de Espacios Naturales Protegidos, C/San Sebastian 71, 28791 Soto del Real (Madrid), Spain 2 Centre d' Estudis Avancats, Cam( Sta. Barbara s/n, 17300 Blanes (Gerona), Spain 3 Departamento de Biologla Animal y Ecologla, Facultad de Biologla, Universidad de Murcia, Campus de Espinardo, 30071 Murcia, Spain
Received 1 March 1995 ; in revised form 18 October 1995 ; accepted 6 December 1995
Key words : Heteroptera, distribution, associations, Balearic Islands
Abstract Twenty-five species of aquatic Heteroptera were collected from the Balearic Islands . Five are first records (Sigara nigrolineata, Micronecta scholtzi, Ranatra linearis, Notonecta meridionalis and Hebrus pusillus) . Previous records are also discussed . The spatial structure of the communities on the Islands is analysed . The different abundance of species and their characteristic habitats are identified . The species associations for each island are established through factorial analysis (correspondence analysis) ; a total of 8 associations are defined . They represent permanent habitats, with the exception of one, characteristic of seasonal ponds of Mallorca . Within the permanent lentic habitats, a clear difference occurs between artificial habitats ('albercas' : stone or cemented man-made irrigation ponds) and natural pond habitats .
Introduction
Material and methods
The Heteroptera of the Balearic Islands are relatively well known, with studies published since the last (Ramis, 1814 ; Bolfvar & Chicote, 1879 ; Moragues, 1894) as well as in the present century (Saunders, 1901 ; Royer, 1906 ; Garcfas, 1907 ; Torre, 1911 ; S'anchez, 1918 ; Eidmann, 1927 ; Villarrubia & Espanol, 1933 ; Espanol, 1935 ; Tamanini, 1948, 1949 ; Palau, 1949 ; Margalef, 1951, 1952, 1953 ; Bigot, 1958 ; Compte, 1960 ; Ribes, 1965, Compte, 1968 ; Tamanini, 1971 ; Ribes, 1977, 1978, 1984 ; Pons, 1987 ; Nieser & Montes, 1988) . Yet, most deal only with single islands and do not discuss habitat preferences . In this study, we provide a synoptic information and describe species associations and ecological preferences .
A total of 246 sites (120 in Mallorca, 68 in Menorca, 41 in Ibiza and 17 in Formentera) were sampled in winter (February and March 1988) and spring (May and June 1988) (Garcfa-Avilt s, 1990) using a 30 cm square net with 100 ,am mesh size . Figure 1 shows the geographical location of the Balearic Islands ; Table 1 provides a summary of the types of habitat of the sampling sites . Specimens were identified using the keys of Tamanini (1979), Jansson (1986), Poisson (1957), Macan (1976), Murillo (1985) and Milldn et al. (1987) . In order to define species associations, a multiple correspondence factorial analysis, version SPAD .N (Lebart et al ., 1987), was applied to each of the islands . In this analysis presence/absence data were used . Stations lacking Heteroptera were not eliminated from the analysis .
210 Table 1 . Location and characteristics of the sampling sites
Habitat
Sites
Stream
Pond
'Alberca'
Marsh Spring
Reservoir
Mallorca
Menorca
2, 3, 6, 7, 8, 9, 10, 11, 12, 14, 15, 26, 27, 28, 31, 34, 36, 37, 38, 39, 62, 63, 65, 66, 69, 72, 73, 81, 83, 84, 85, 86, 88, 90, 92, 94, 100, 103, 104, 105, 108, 109, 111, 112, 119. 4, 13, 17, 18, 19, 20, 21, 22, 23, 24, 25, 47, 48, 50, 52, 53, 54, 55, 57, 58, 61, 93, 116, 117 .
125, 138, 147, 158, 165, 174, 184, 121, 135, 152, 176,
16, 43, 51, 56, 59, 60, 67, 71, 77, 78, 79, 80, 89, 95, 96, 97, 99, 106, 110, 114, 120 . 29, 30, 35, 40, 41, 42, 44, 45, 46, 101 . 1, 5, 32, 33, 49, 64, 68, 70, 76, 82, 87, 91, 98, 102, 107, 113, 115, 118 . 74, 75 .
153, 166, 173, 188 .
126, 132, 139, 140, 148, 149, 159, 160, 167, 168, 175, 181, 186 . 122, 124, 141, 143, 154, 155, 178, 185 .
136, 142, 151, 161, 171, 182,
137, 145, 157, 164, 172, 183,
131, 134, 144, 150, 156, 162,
123, 127, 128, 129, 130, 133, 146, 169, 177 . 163, 170, 179, 180, 187 .
Ibiza
Formentera
190, 191, 208, 209, 213, 216, 223 .
237, 238, 239 .
201, 207, 229 .
234, 240, 241, 243, 244, 246 .
189, 200, 214, 220, 202,
242 .
192, 195, 196, 197, 203, 205, 210, 212, 215, 217, 218, 219, 221, 222 . 226 .
230, 231, 232, 235, 236, 245 . 233 .
193, 194, 198, 199, 204, 206, 211, 224, 225, 227, 228 .
Table 2. Definitions of Abundance of each
MENORC ;,
species on each island Abundance
Proportion of sites from which recorded
Very abundant IBIZA
(~
0
30 km
Abundant Common Scarce Rare Very rare
> 50% 30%-50% 15%-29% 5%-14%
