Baby Spiders Really Take It Out of Moms

In at least one species of spider, numerous females will care for the babies of the one female with offspring. And all the females will be consumed by the next generation. Cynthia Graber reports.

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Talk about maternal sacrifice.  In a rather freakish twist of nature, baby spiders in some species completely devour their moms.  And now researchers have discovered that the practice can get even stranger.  Scientists from Israel’s Ben Gurion University wanted to know if spiders participate in cooperative group mothering, as some mammals and birds do.  They investigated a species of spider from southern Africa known for maternal care and for communal living.  The results appear in the journal Behavioral Ecology and Sociobiology.

In some experimental nests, the researchers left a group of females intact but removed egg sacks from all but one of the mothers-to-be.  In control groups there was only one female and her eggs.  At the end of the study, they checked on the health of the spider babies.  In those groups with multiple moms, more eggs successfully hatched and the brood was healthier overall.  As for the moms?  They were almost all sucked dry, leaving only their crispy exoskeletons.  So now at least one species of spider is known to participate in communal mothering.  And under the right circumstances even the surrogate moms sacrificing everything for the offspring.

—Cynthia Graber

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