Homework SourseFate of Cosmosoma offered to N clavipes spiders Males alkal
Solution
Males of the moth Cosmosoma myrodora acquire pyrrolizidine alkaloid by feeding on the excrescent fluids of certain plants.Incorporating the alkaloid protect them against spiders.The males discharge the filaments containing alkaloid on the female during courtship,thereby protects the female against spiders. Alkaloid deprived males are the prey for the spiders. The males also transmit alkaloid to the female by seminal infusion. The systemic alkaloid thus received, defend the females against spiders. Protective nuptial festooning of a female by its mate is also practiced by C. myrodora.
According to the graph,
Males (all virgin) that are offered to N. clavipes respond differently depending on whether they had intaken alkaloid. Seven males that had fed on the alkaloid were living and not eaten by the spiders.
Whereas, males that had had no access to alkaloid were eaten.
In case of females,
Seven females mated as virgins to alkaloid-bearing males were all saved.
Females that had mated with alkaloid-free males were eaten.
Virgin alkaloid free females were eaten as well.
In case of Flocculent-Treated Females,
Eight virgin females that were coated with flocculent from males, had no access to alkaloid and were eaten by N. clavipes. On the other hand, over half of the virgin females that were coated with flocculent from males that had fed on the alkaloid were set free by the spider.
Significance of the value : Not all males released flocculent on encountering the female. Of the males that were tested few delivered flocculent, and few does not. The former group was significantly more successful in securing copulations than the latter group. (P < 0.05, 2 test).
