ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Spontaneous egg-laying in the carnivorous marine gastropodPleurobranchaea californica is accompanied by elevation of the feeding response threshold (Fig. 1), an adaptation that presumably prevents specimens from eating their own eggs. Injection of blood from egg-laying animals induces egg-laying and elevation of the feeding response threshold in non-laying specimens (Fig. 2). Therefore, the causal agent is blood-borne and presumably a hormone(s). Injection of crude extract of whole nervous systems taken from egg-laying specimens induces egg-laying and elevation of the feeding threshold in non-laying specimens (Figs. 3A, 4A, 5, 6, 7). Therefore, the hormone(s) is contained within the central nervous system of egg-laying specimens. Injection of crude extract of whole nervous systems taken from non-laying specimens weakly induces egg-laying, but not elevation of the feeding threshold, in non-laying specimens (Figs. 3B, 4B). Therefore, the hormone(s) may be present, in small quantities, in the central nervous system of non-laying specimens. Injection of sea water into non-laying specimens neither induces egg-laying nor elevates the feeding response threshold (Figs. 3C, 4C). Therefore, the above effects were not caused simply by the trauma of injection. Injection of crude extract of whole nervous systems taken from egg-laying specimens does not influence withdrawal responses (Figs. 8, 9) or righting behavior (Figs. 10, 11). Therefore, the hormone(s) is selective in its suppressive effect, preferentially inhibiting feeding but not other behaviors. These data support the hypothesis that one or more hormone(s) is released by the nervous system into the blood to induce egg-laying and simultaneously and selectively suppress feeding behavior. The study shows that egg-laying occupies a more dominant position than feeding in the behavioral hierarchy ofPleurobranchaea, and suggests that the dominance is mediated hormonally (Fig. 12).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00701475
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