TY - JOUR
T1 - Sexual and parthenogenetic populations of the freshwater snail melanoides tuberculata in Israel
AU - Heller, Joseph
AU - Farstey, Viviana
PY - 1990
Y1 - 1990
N2 - Melanoides tuberculata ranges from far-eastern Asia into Africa. Throughout much of its distribution it reproduces parthenogenetically. In Israel however, males have been found. This study investigates whether sex ratios of M. tuberculata are related to frequency of trematode infections, faunal diversity and chemistry of water. Thirty-four populations were sampled. Seven of these contained no males, fifteen contained less than 10%, ten had 10–36%, one had 46% and one had 66% males. Male frequency is not related to trematode infection, neither to their overall frequency nor to the frequency of those parasites which could be identified specifically. Infection frequency is lower in males than in females and higher in large females than in small ones. These results do not support the view that sex is favoured by selection resulting from host-parasite interactions. Male frequency is not related to habitat diversity either, as expressed by the number of mollusc genera found at a site. It is negatively related to magnesium, potassium and chloride concentrations in the water. Several addition& findings result from the study: Very sparse populations lack males; The most stable, predictable habitats have lower-than-average frequencies; The two highest male frequencies are found in habitats that are at the same time highly unstable (water bodies that were dry in the last two years), densely populated and have M. tuberculata as the sole or overwhelmingly major genus.
AB - Melanoides tuberculata ranges from far-eastern Asia into Africa. Throughout much of its distribution it reproduces parthenogenetically. In Israel however, males have been found. This study investigates whether sex ratios of M. tuberculata are related to frequency of trematode infections, faunal diversity and chemistry of water. Thirty-four populations were sampled. Seven of these contained no males, fifteen contained less than 10%, ten had 10–36%, one had 46% and one had 66% males. Male frequency is not related to trematode infection, neither to their overall frequency nor to the frequency of those parasites which could be identified specifically. Infection frequency is lower in males than in females and higher in large females than in small ones. These results do not support the view that sex is favoured by selection resulting from host-parasite interactions. Male frequency is not related to habitat diversity either, as expressed by the number of mollusc genera found at a site. It is negatively related to magnesium, potassium and chloride concentrations in the water. Several addition& findings result from the study: Very sparse populations lack males; The most stable, predictable habitats have lower-than-average frequencies; The two highest male frequencies are found in habitats that are at the same time highly unstable (water bodies that were dry in the last two years), densely populated and have M. tuberculata as the sole or overwhelmingly major genus.
UR - http://www.scopus.com/inward/record.url?scp=0025525547&partnerID=8YFLogxK
U2 - 10.1080/00212210.1990.10688643
DO - 10.1080/00212210.1990.10688643
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AN - SCOPUS:0025525547
SN - 0021-2210
VL - 37
SP - 75
EP - 87
JO - Israel Journal of Zoology
JF - Israel Journal of Zoology
IS - 2
ER -