Mitigating thermal effect of behaviour and microhabitat on the intertidal snail Littorina saxatilis (Olivi) over summer

Littorina saxatilis, the rough periwinkle, is highly promiscuous and polyandrous; female L. saxatilis snails rarely reject male advances. Sexual selection by males has been observed in this species. Sexual selection is one of the driving forces of evolution and may be a significant contributor to partial reproductive isolation between two ecotypes of L. saxatilis. Male sexual selection based on female size was investigated for wave-exposed crab ecotype snails in this study. Males and females were measured and placed in mating arenas. Males were presented with a choice of a smaller or larger female relative to themselves. Mating frequency and duration was recorded. A total of 19 successful trials were performed. A significantly higher mating frequency (p<0.005) was associated with larger females, indicating that males exhibit strong pre-copulatory sexual selection. Mating duration was significantly longer for larger female mating events (p<0.05) but was also equally determined by male size (p<0.05) as larger males tended to mate for longer. These results indicate that a strong sexual selection by males exists for L. saxatilis, in which larger females are preferred. This behavior may be a response to perceived fecundity of females, and/or may be a product of selection against hybrids.

Download Full-text

Ecological Speciation and the Intertidal Snail Littorina saxatilis

Advances in Ecology ◽

10.1155/2014/239251 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 11

Author(s):

Juan Galindo ◽

John W. Grahame

Keyword(s):

Single Species ◽

Ecological Speciation ◽

Reproductive Barriers ◽

Littorina Saxatilis ◽

Good Case ◽

Future Developments ◽

Geographical Barrier ◽

Intertidal Snail

In recent decades biologists studying speciation have come to consider that the process does not necessarily require the presence of a geographical barrier. Rather, it now seems to be possible for reproductive barriers to evolve within what was hitherto a single ‘‘species.’’ The intertidal snail Littorina saxatilis has been the focus of a considerable amount of work in this context, and it is now thought of as a good case study of ‘‘ecological speciation.’’ We review some of this work and briefly consider prospects for future developments.

Download Full-text

UHV-STM studies of silicon nano-pyramid growth on silicon surface at high temperature

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130353 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1144-1145

Author(s):

T. Sato ◽

S. Kitamura ◽

T. Sueyoshl ◽

M. Iwatukl ◽

C. Nielsen

Keyword(s):

High Temperature ◽

Relaxation Process ◽

Thermal Effect ◽

Bias Voltage ◽

Silicon Surface ◽

Growth Process ◽

Tunneling Current ◽

Fabrication Technique ◽

Nano Fabrication ◽

Electromigration Effect

Recently, the growth process and relaxation process of crystalline structures were studied by observing a SI nano-pyramid which was built on a Si surface with a UHV-STM. A UHV-STM (JEOL JSTM-4000×V) was used for studying a heated specimen, and the specimen was kept at high temperature during observation. In this study, the nano-fabrication technique utilizing the electromigration effect between the STM tip and the specimen was applied. We observed Si atoms migrated towords the tip on a high temperature Si surface.Clean surfaces of Si(lll)7×7 and Si(001)2×l were prepared In the UHV-STM at a temperature of approximately 600 °C. A Si nano-pyramid was built on the Si surface at a tunneling current of l0nA and a specimen bias voltage of approximately 0V in both polarities. During the formation of the pyramid, Images could not be observed because the tip was stopped on the sample. After the formation was completed, the pyramid Image was observed with the same tip. After Imaging was started again, the relaxation process of the pyramid started due to thermal effect.

Download Full-text