JayB Posted November 23, 2011 Posted November 23, 2011 "Male Spiders Scam Females with Gift-Wrapped Garbage Male nursery web spiders lure mates with silk-wrapped offerings, only some of which contain tasty treats. Male nursery web spiders often woo potential lady-friends with gifts wrapped in silk. Mating may ensue, during which a female unspools the present, expecting to find a tasty treat. But the males can be unscrupulous. Some offerings contain inedible plant seeds or empty insect exoskeletons. How do males get away with such egregious behavior? Researchers provided males with potential gifts—either a fly or an inedible item, such as a bit of cotton. Other males had to give it a shot with no gift at all. The empty-handed males were mostly unsuccessful at mating. Whereas those with a gift could get the girl. But if the gift was worthless, the females quickly realized the deceit and pushed the copulating males off. Which gave the males less time to transfer sperm. Females clearly prefer males bearing edible presents. But some males know they can get limited action without expending the energy on a real gift. And the females laid almost the same amount of eggs fertilized by males bearing real or phony gifts. With both strategies successful, the behavior gets maintained. And the species stays stocked with deadbeat dads." http://www.scientificamerican.com/podcast/episode.cfm?id=male-spiders-scam-females-with-gift-11-11-21 Quote
tvashtarkatena Posted November 24, 2011 Posted November 24, 2011 Me bro in law just recovered from a brown recluse bite. You really don't want to be bitten by one of those guys if you can avoid it. Fun Fact: a spider's 'blood' is copper, not iron, based. Quote
sobo Posted November 24, 2011 Posted November 24, 2011 Fun Fact: a spider's 'blood' is copper, not iron, based. So spiders are Vulcan in origin? Fascinating... Quote
tvashtarkatena Posted November 24, 2011 Posted November 24, 2011 Copper's less efficient than iron at transferring oxygen, but hey, evolution is kind of like Windows.... Quote
rob Posted November 24, 2011 Posted November 24, 2011 maybe spiders just don't need a lot of oxygen, so there was never an evolutionary need for better oxygen transport? And rather than hemoglobin, they use a far more complicated transport system which allows their blood to release more or less oxygen depending on the need of the cells based on various chemical signals; also, I think they're able to use this special blood to raise their blood pressure somehow to initiate molting. I saw a PBS show on this once. Really cool stuff -- their blood is clear, too, and their circulatory system is mostly open (i.e. the blood flows freely between major organs with a very minor vascular/capillary system in place). Quote
tvashtarkatena Posted November 24, 2011 Posted November 24, 2011 Also, when spiders evolved, there was more oxygen in the atmosphere than there is today. Maybe. I didn't check. Sounds good, anyway. Quote
rob Posted November 24, 2011 Posted November 24, 2011 I wonder where all that oxygen went since then. I blame oxyclean. Quote
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