November 10, 2009
1) The news article claims that Evarcha culicivora uses blood as a perfume to attract the opposite sex. The author, Charles Q. Choi, claims that researchers found these spiders like to hunt bloodsuckers, such as mosquitoes with the deadly malaria parasite, suggesting that this species of spider could help to control the disease. Choi states that research shows that spiders who fed on blood-fed mosquitoes were sexier to members of the opposite sex. Those on non-blood diet who switch to blood-fed mosquitoes became more attractive. Vise-visa, spiders of the opposite sex lose interest in those who change from blood-fed mosquitoes to blood-free diet. Most of these claims are supported by the study. The only claim not supported is that these spiders enjoy hunting bloodsuckers contracting malaria.
2) Yes, the article does discuss the findings in the conclusions section of the study. The study discusses three major items in the conclusion. First, E. culicivora males and females feeding on bloodcarrying mosquitoes have odor that are more attractive to the opposite sex. Second, the next steps are to determine whether spiders on blood diets really are more successful at mating. Lastly, the study only found evidence of acquired odor making the individual more attractive only when the source spider was an opposite-sex conspecific individual. Unless euglossin males who have problems with their odor attracting other males, the odor of E. culicivora doesn't attract members of the same-sex. The article discusses that E. culicivora feeding on bloodcarrying mosquitoes have odor that are more attractive to the opposite sex and the future experiments the researches would like to carry out. However, it does not talk about possible attraction of same-sex individuals.
3) The researchers comments on the fact that their experiment precludes actually mating. They only measured Evarcha culicivora attraction to the odor of blood diets. However, based on the results from previous studies of spider, they state that the experimental design used is an accurate indicator of mate-choice decisions. Since the researchers were very confident about their results, the author does not make any refer to the degrees of uncertainty.
4) There are examples of the report discussing “broader implications” not presented in the original paper. The original paper does discuss that it is common for animal courtship routines to be based on the use of odors. It goes further to list examples such as male fruit flies attracting potential mates by using ginger root oil as a perfume, or that the attraction of salamanders is based on their diet based odor. The article talks about all this but also links this study to include humans by stating that “in human relationships, resources often play an important role in whether an animal is accepted as a mate ...they reflect the quality of a potential mate's territory, or the quality of a nuptial gift, usually food, presented during courtship.” Furthermore, the article discusses that this species of spider can be used to control malaria and other bloodsuckers contracting diseases.
5) The technical paper does not describe previous contradictory work which is overturned in this experiment. Instead, it reinforces previous studies that odor derived from diet is used to attract potential mates as in the case of salamanders and fruit flies. The article does talk about odor based diets and its' use for attractions in other species.
6) This article does not couch science as debate between equal sides. It does not mention alternative hypotheses but only summaries and enforces the important claims the technical paper made.