SAMPLINGS 



Babbling baby: a young greater 

 sac-winged bat 



Side Benefits 



Like right- or left-handed people, most 

 animals seem to favor one side of their 

 bodies for certain tasks. Lateralized be- 

 havior is a sign that the animals' brains 

 are lateralized as well. But is there any 

 benefit to having a lateralized brain? A 

 recent study by Marco Dadda, a psychol- 

 ogist, and Angelo Bisazza, an evolution- 

 ary biologist, both at the University of 

 Padua in Italy, suggests that lateralization 

 may make animals better at the critical 

 skill of multitasking — attending to two or 

 more activities at the same time. 



Goldbelly topminnows are small 

 Central American fish that belong to the 

 guppy family. Female goldbelly topmin- 

 nows must put up with repeated 

 attempts by males to mate with them. 

 The suitors can be distracting, even 

 exasperating, to females, particularly 

 when they are trying to eat. Dadda and 

 Bisazza compared the feeding efficiency 

 of female goldbelly topminnows bred to 

 be lateralized with that of females bred 

 to have no side preference. When there 

 were no distracting males, the two kinds 

 of females caught food equally well. 

 When randy males were present, howev- 

 er, only the lateralized females kept eat- 

 ing efficiently, while still avoiding 

 unwanted advances. Parallel processing 

 seems to benefit from a brain with asym- 

 metrical function. (Behavioral Ecology 

 17:358-63, 2006) —Stephan Reebs 



Baby Bat Chat 



"Goo-goo ga-ga" is an important step for a 

 baby learning the intricacies of human lan- 

 guage. Babies babble away with complete 

 disregard for social context, happily practic- 

 ing the sounds they will need to speak as 

 adults. Only a handful of other animals, all 

 with advanced vocal skills— a few primates, 

 certain birds, and maybe some whales and 

 dolphins — babble when they are young. Now 

 a new creature has joined that elite group: 

 the greater sac-winged bat of Central and 

 South America, Saccopteryx bilineata. 



The greater sac-winged bat is a chatty 

 creature. Not only does it make sounds to 



Burgers and Flies 



Grab that flyswatter! Public-health ento- 

 mologists have discovered antibiotic- 

 resistant bacteria lurking in the guts of 

 houseflies buzzing around fast-food joints. 

 Ludek Zurek and Lilia Macovei of Kansas 

 State University in Manhattan, Kansas, 

 captured more than 200 houseflies at five 

 restaurants in a northeastern Kansas town. 

 The entomologists isolated and cultured 

 bacteria from the flies' guts, then exposed 

 the bacteria to antibiotics. Two-thirds of 

 the bacteria survived treatment with a sin- 

 gle common antibiotic, and, of those, half 

 survived treatment with two or more antibi- 

 otics. Zurek and Macovei also identified 

 genes that confer immunity in most of the 

 resistant bacteria's DNA. 



The houseflies may have come from 

 farms, the entomologists say. In the U. S., 

 livestock are regularly dosed with antibi- 

 otics to encourage growth, and so their gut 

 bacteria often evolve resistance to the 

 drugs. Houseflies that develop in and feed 

 on the animals' waste swallow bacteria 

 when they eat. Then, 

 being long-distance 

 aviators, they can fly to 

 town — hence their nick- 

 name in Zurek's lab: 

 "flying manure." 



Houseflies enjoy many 

 of the same foods peo- 

 ple do, including cooked 

 meat and sweets. And 

 they go to the same 

 restaurants. They eat 

 messily, spitting and 

 regurgitating on their 

 meal before digging in. 

 In the process, a house- 



catch prey by echolocation; it also barks, 

 chatters, screeches, and whistles to attract or 

 threaten other members of its species. Males 

 even serenade females with courtship songs 

 and repel competitors with territorial songs, 

 just as birds do. 



At several roosts in Costa Rica, Mirjam 

 Knornschild, a behavioral ecologist, Otto von 

 Helversen, a zoologist, and a colleague, all 

 from the University of Erlangen-Nuremberg 

 in Germany, recorded sounds made by 

 young sac-winged bats that had not yet 

 been weaned from their mothers. Like baby 

 babbles, the pups' vocalizations were similar 

 to adults' calls, and the pups made them 

 without regard for social context, typically 

 while alone. Intriguingly, pups of both sexes 

 practiced parts of the courtship and territori- 

 al songs sung in adulthood only by males. 

 Babbling, the authors contend, may be 

 essential for any animal to master a large 

 vocal repertoire. (Naturwissenschaften, DOI 

 10.1007/s001 14-006-01 27-9, 2006) 



—S.R. 



fly's lunch — which may be your lunch, too — 

 is doused with the contents of the fly's gut, 

 including any bacteria, antibiotic-resistant or 

 not, that the fly is carrying. 



As unappetizing as that may sound, 

 most gut bacteria from flies are relatively 

 harmless, so their immunity to antibiotics 

 might not seem alarming. But bacteria 

 readily exchange genes, so the gut bacte- 

 ria could pass resistance genes on to nasti- 

 er species, which houseflies also carry. 

 And those little monsters can prove 

 immune to current medical treatments — a 

 mounting concern for physicians. [Applied 

 and Environmental Microbiology 72: 

 4028-35, 2006) — Clara Curtin 



NATURAL HISTORY September 2006 



