164 posts · 172,272 views
Mennonite, evolutionary biologist, cat-4 cyclist. Not necessarily in that order.
Denim and Tweed
161 posts
Nothing in Biology Makes Sense!
3 posts
Sort by Latest Post, Most Popular
View by Condensed, Full
- December 30, 2009
- 10:05 AM
- 958 views
Escaping the "poverty trap" of infectious disease
by Jeremy Yoder in Denim and Tweed
Even in the twenty-first century, infectious diseases such as malaria, dengue fever, cholera, and AIDS remain widespread in much of the developing world, at tremendous cost to human life and economic productivity. Poorer nations lack the resources for more effective public health measures; but widespread infectious disease may slow or prevent the economic development that can provide those resources. A new paper in Proceedings of the Royal Society tries to sort out this chicken-and-egg problem, ........ Read more »
Bonds, M., Keenan, D., Rohani, P., & Sachs, J. (2009) Poverty trap formed by the ecology of infectious diseases. Proc. R. Soc. B. DOI: 10.1098/rspb.2009.1778
- December 23, 2009
- 10:05 AM
- 784 views
Why aren't there more sickle-cell anemics in the Mediterranean?
by Jeremy Yoder in Denim and Tweed
The story of sickle-cell anemia and its malaria-protective effects is a textbook case how environmental context determines the fitness of a given genetic profile. However, the evolution of human blood disorders in response to selection from malaria parasites might be more complicated than that textbook story.
.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; }
Malaria-cau........ Read more »
Penman, B., Pybus, O., Weatherall, D., & Gupta, S. (2009) Epistatic interactions between genetic disorders of hemoglobin can explain why the sickle-cell gene is uncommon in the Mediterranean. Proc. Nat. Acad. Sci. USA, 106(50), 21242-6. DOI: 10.1073/pnas.0910840106
- December 16, 2009
- 10:05 AM
- 757 views
Cuckholding crows don't necessarily have fitter chicks
by Jeremy Yoder in Denim and Tweed
Birds are bad at monogamy. There are a number of good evolutionary reasons to cheat on your mate, and it's not clear which one is the most likely explanation. A new study of American crows, however, suggests that, for females, cheating isn't necessarily the best choice [$-a].
Avian infidelity isn't obvious, because many birds are socially monogamous, forming couples for one or more breeding seasons to raise chicks. However, DNA-based paternity testing has overturned this intuition -- a 2002 rev........ Read more »
Arnqvist, G., & Kirkpatrick, M. (2005) The evolution of infidelity in socially monogamous passerines: The strength of direct and indirect selection on extrapair copulation behavior in females. The American Naturalist, 165(s5). DOI: 10.1086/429350
Griffith, S.C., Owens, I.P.F., & Thuman, K.A. (2002) Extrapair paternity in birds: A review of interspecific variation and adaptive function. Molecular Ecology, 2195-212. info:/10.1046/j.1365-294X.2002.01613.x
Townsend, A., Clark, A., & McGowan, K. (2010) Direct benefits and genetic costs of extrapair paternity for female American Crows (Corvus brachyrhynchos). . The American Naturalist, 175(1). DOI: 10.1086/648553
- December 10, 2009
- 10:05 AM
- 717 views
Picky eating, not genetics, splits leaf beetles
by Jeremy Yoder in Denim and Tweed
Many different factors can conspire to create reproductive isolation between populations and, ultimately, separate species. Disentangling them is often tricky, but a study recently published in PNAS takes a crack, and demonstrates that two populations of leaf beetles are divided by food preferences, not genetics [$-a]
.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; }
N........ Read more »
Bikard, D., Patel, D., Le Mette, C., Giorgi, V., Camilleri, C., Bennett, M., & Loudet, O. (2009) Divergent evolution of duplicate genes leads to genetic incompatibilities within A. thaliana. Science, 323(5914), 623-6. DOI: 10.1126/science.1165917
Egan, S., & Funk, D. (2009) Ecologically dependent postmating isolation between sympatric host forms of Neochlamisus bebbianae leaf beetles. Proc. Nat. Acad. Sci. USA, 106(46), 19426-19431. DOI: 10.1073/pnas.0909424106
- December 2, 2009
- 10:05 AM
- 902 views
For yucca moths, does (flower) size matter?
by Jeremy Yoder in Denim and Tweed
In a paper just released online at Molecuar Ecology ahead of publication, genetic tests on moth larvae provide the latest piece to the puzzle of why there are two kinds of Joshua tree -- because the tree's pollinators need to match its flowers [PDF].
I've written extensively about the interaction between Joshua tree and its pollinators. Like all yuccas, Joshua tree is pollinated only by yucca moths. Female yucca moths collect pollen in special mouthparts and deliberately apply it to a yucca flo........ Read more »
Godsoe, W., Yoder, J.B., Smith, C., & Pellmyr, O. (2008) Coevolution and divergence in the Joshua tree/yucca moth mutualism. The American Naturalist, 171(6), 816-823. DOI: 10.1086/587757
Marr, D., & Pellmyr, O. (2003) Effect of pollinator-inflicted ovule damage on floral abscission in the yucca-yucca moth mutualism: the role of mechanical and chemical factors. Oecologia, 136(2), 236-243. DOI: 10.1007/s00442-003-1279-3
Smith, C., Godsoe, W., Tank, S., Yoder, J.B., & Pellmyr, O. (2008) Distinguishing coevolution from covicariance in an obligate pollination mutualism: Asynchronous divergence in Joshua tree and its pollinators. Evolution, 62(10), 2676-87. DOI: 10.1111/j.1558-5646.2008.00500.x
Smith, C.I., Drummond, C., Godsoe, W.K.W., Yoder, J.B., & Pellmyr, O. (2009) Host specificity and reproductive success of yucca moths (Tegeticula spp. Lepidoptera: Prodoxidae) mirror patterns of gene flow between host plant varieties of the Joshua tree (Yucca brevifolia: Agavaceae). . Molecular Ecology. DOI: 10.1111/j.1365-294X.2009.04428.x
- November 23, 2009
- 09:05 AM
- 1,117 views
Aphid-tending ants cull the sick from the herd
by Jeremy Yoder in Denim and Tweed
Just released online at Biology Letters: aphid-tending ants have been observed to selectively remove sick members of their "herd" [$-a].
Most aphid species produce some sort of sweet honeydew as waste while feeding on their host plants; ant-attended aphid species use this honeydew to attract ants. In many cases, the ants "milk" the aphids by stroking them to prompt release of the honeydew. While exploiting a colony of aphids, ants defend it as a food resource, protecting the aphids from predato........ Read more »
Nielsen, C., Agrawal, A., & Hajek, A. (2009) Ants defend aphids against lethal disease. Biology Letters. DOI: 10.1098/rsbl.2009.0743
Way, M. (1963) Mutualism between ants and honeydew-producing Homoptera. Ann. Rev. Entomology, 8(1), 307-44. DOI: 10.1146/annurev.en.08.010163.001515
- November 20, 2009
- 09:05 AM
- 1,112 views
Cost of killing nest-mates offset by benefits of killing nest-mates
by Jeremy Yoder in Denim and Tweed
Among birds, brood parasites are the ultimate freeloaders -- species like the common cuckoo and the brown-headed cowbird lay their eggs in other birds' nests, leaving the host to raise the parasite chicks at the expense of its own. But while brood parasitism is easy on the parents, it isn't so easy on their chicks, as a study recently published in PLoS ONE suggests.
.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-c........ Read more »
Anderson, M., Moskát, C., Bán, M., Grim, T., Cassey, P., & Hauber, M. (2009) Egg eviction imposes a recoverable cost of virulence in chicks of a brood parasite. PLoS ONE, 4(11). DOI: 10.1371/journal.pone.0007725
Hoover, J., & Robinson, S. (2007) Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs. Proc. Nat. Acad. Sci. USA, 104(11), 4479-83. DOI: 10.1073/pnas.0609710104
Lahti, D. (2005) Evolution of bird eggs in the absence of cuckoo parasitism. Proceedings of the National Academy of Sciences, 102(50), 18057-62. DOI: 10.1073/pnas.0508930102
Soler, M., Soler, J., Martinez, J., & Moller, A. (1995) Magpie host manipulation by great spotted cuckoos: Evidence for an avian mafia?. Evolution, 49(4), 770-5. DOI: 10.2307/2410329
- November 9, 2009
- 11:05 AM
- 975 views
Pollination before flowers
by Jeremy Yoder in Denim and Tweed
Which came first, the pollinator or the pollinated? An article in this week's Science suggests that a diverse group of insects may have been drinking nectar and pollinating plants millions of years before the appearance of modern flowering plants [$-a].
.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; }
Panorpis communis, a modern scorpionfly species, and a sketch of anc........ Read more »
Ollerton, J., & Coulthard, E. (2009) Evolution of animal pollination. Science, 326(5954), 808-9. DOI: 10.1126/science.1181154
Ren, D., Labandeira, C., Santiago-Blay, J., Rasnitsyn, A., Shih, C., Bashkuev, A., Logan, M., Hotton, C., & Dilcher, D. (2009) A probable pollination mode before angiosperms: Eurasian, long-proboscid scorpionflies. Science, 326(5954), 840-7. DOI: 10.1126/science.1178338
- October 29, 2009
- 02:02 PM
- 1,121 views
Endless forms: Oral sex by fruit bats
by Jeremy Yoder in Denim and Tweed
One of those scientific papers that seems to have been written with the blogosphere in mind: biologists have just published records of fellatio by the fruit bat Cynopterus sphinx. Apparently C. sphinx females are pretty flexible -- they lick their mate's penis during copulation, which evidently induces him to stay in longer (see the graph below, with drawing). The authors offer a handful of non-mutually-exclusive hypotheses for the adaptive benefit of the behavior, ranging from lubrication to in........ Read more »
Tan, M., Jones, G., Zhu, G., Ye, J., Hong, T., Zhou, S., Zhang, S., & Zhang, L. (2009) Fellatio by fruit bats prolongs copulation time. PLoS ONE, 4(10). DOI: 10.1371/journal.pone.0007595
- October 26, 2009
- 12:05 PM
- 957 views
How to synchronize flowering without really trying
by Jeremy Yoder in Denim and Tweed
One way plants can gain an advantage in their dealings with pollinators, seed dispersers, or herbivores is to act collectively. For instance, when oak trees husband their resources for an extra-big crop of acorns every few years instead of spreading them out, acorn-eating rodents are overwhelmed by the bumper crop, and more likely to miss some, or even forget some of the nuts they cache. These benefits of synchronized mass seed production, or "masting," are straightforward, but how it happens is........ Read more »
Crone, E., Miller, E., & Sala, A. (2009) How do plants know when other plants are flowering? Resource depletion, pollen limitation and mast-seeding in a perennial wildflower. Ecology Letters, 12(11), 1119-26. DOI: 10.1111/j.1461-0248.2009.01365.x
Janzen, D. (1971) Seed Predation by Animals. Ann. Rev. Ecol. Syst., 2(1), 465-92. DOI: 10.1146/annurev.es.02.110171.002341
Janzen, D. (1976) Why Bamboos Wait So Long to Flower. Ann. Rev. Ecol. Syst., 7(1), 347-91. DOI: 10.1146/annurev.es.07.110176.002023
Satake, A., & Iwasa, Y. (2000) Pollen coupling of forest trees: Forming synchronized and periodic reproduction out of chaos. J. Theoretical Biol., 203(2), 63-84. DOI: 10.1006/jtbi.1999.1066
- October 19, 2009
- 12:05 PM
- 754 views
Social termites team up with non-relatives
by Jeremy Yoder in Denim and Tweed
In social insects, colonies of hundreds or thousands of workers and soldiers forgo reproduction to support one or a few "reproductives" -- drones and a queen. In most cases, this isn't as selfless as it might seem. Because the workers in a colony are all offspring of the queen, they're really reproducing through her -- because the queen shares genes with the workers, when she reproduces it contributes to their evolutionary fitness.
This is called kin selection, and in many cases it's a good exp........ Read more »
SMITH, J. (1964) Group selection and kin selection. Nature, 201(4924), 1145-1147. DOI: 10.1038/2011145a0
Johns, P., Howard, K., Breisch, N., Rivera, A., & Thorne, B. (2009) Nonrelatives inherit colony resources in a primitive termite. Proc. Nat. Acad. Sci. USA, 106(41), 17452-6. DOI: 10.1073/pnas.0907961106
- October 13, 2009
- 03:30 PM
- 972 views
Video of yucca pollination
by Jeremy Yoder in Denim and Tweed
With permission from my doctoral advisor, Olle Pellmyr, I've just uploaded a unique video to Vimeo: a yucca moth laying eggs in, then pollinating, a yucca flower. I don't know why I didn't think of this earlier -- it's great footage, and deserves to be seen more widely.
A female yucca moth mates, then collects pollen from a yucca flower in specialized mouthparts. She carries it to another flower where, as shown in the video, she drills into the floral pistil with her ovipositor and lays eggs ........ Read more »
Godsoe, W., Yoder, J., Smith, C., & Pellmyr, O. (2008) Coevolution and Divergence in the Joshua Tree/Yucca Moth Mutualism. The American Naturalist, 171(6), 816-23. DOI: 10.1086/587757
Pellmyr, O. (2003) Yuccas, yucca moths, and coevolution: A review. Annals of the Missouri Botanical Garden, 90(1), 35. DOI: 10.2307/3298524
Smith, C., Godsoe, W., Tank, S., Yoder, J., & Pellmyr, O. (2008) Distinguishing coevolution from covicariance in an obligate pollination mutualism: Asynchronous divergence in Joshua tree and its pollinators. Evolution, 62(10), 2676-87. DOI: 10.1111/j.1558-5646.2008.00500.x
- October 12, 2009
- 03:05 AM
- 946 views
First step to mutualism doesn't look so friendly
by Jeremy Yoder in Denim and Tweed
Ant-plant protection mutualism is a widespread and elegant species interaction. How do species strike bargain like this, requiring specialized behaviors and structures in each partner, in the first place? A new report in The American Naturalist suggests an answer: maybe ants took the initiative [$-a].
In exchange for protection from herbivores and competitors [big PDF], "myrmecophytic" host plants grow hollow structures called domatia and often produce nectar to shelter and feed a colony of ant........ Read more »
Edwards, D., Frederickson, M., Shepard, G., & Yu, D. (2009) A plant needs ants like a dog needs fleas: Myrmelachista schumanni ants gall many tree species to create housing. The American Naturalist, 174(5), 734-40. DOI: 10.1086/606022
Frederickson, M., Greene, M., & Gordon, D. (2005) "Devil's gardens" bedevilled by ants. Nature, 437(7058), 495-6. DOI: 10.1038/437495a
Janzen, D. (1966) Coevolution of mutualism between ants and acacias in Central America. Evolution, 20(3), 249-75. DOI: 10.2307/2406628
- October 10, 2009
- 12:05 PM
- 577 views
Aiming at a moving target with a shaky pistol: Evolution in a random, changing world
by Jeremy Yoder in Denim and Tweed
Biologists can become distinctly cranky when we hear evolution described as "random." This is because evolution isn't random -- it's undirected. Although it acts on mutations that turn up randomly, natural selection is highly nonrandom, in that (all else being equal) traits that help their owners make more babies are always the ones that spread through a population.
However, even if natural selection predictably aims for the same target, that target is not necessarily fixed. The most obvious ca........ Read more »
Gandon, S., & Day, T. (2009) Evolutionary epidemiology and the dynamics of adaptation. Evolution, 63(4), 826-38. DOI: 10.1111/j.1558-5646.2009.00609.x
Grant, P., & Grant, R. (2002) Unpredictable evolution in a 30-year study of Darwin's finches. Science, 296(5568), 707-11. DOI: 10.1126/science.1070315
Rice, S. (2008) A stochastic version of the Price equation reveals the interplay of deterministic and stochastic processes in evolution. BMC Evolutionary Biology, 8(1), 262. DOI: 10.1186/1471-2148-8-262
Rice, S., & Papadopoulos, A. (2009) Evolution with stochastic fitness and stochastic migration. PLoS ONE, 4(10). DOI: 10.1371/journal.pone.0007130
- October 1, 2009
- 04:05 PM
- 741 views
Empirical pacifism?
by Jeremy Yoder in Denim and Tweed
Slogger Charles Mudede points to a new epidemiological study on the effectiveness of carrying a gun for self defense [$-a]. Not only does packing heat fail to help in the event of an armed robbery,... individuals in possession of a gun were 4.46 (P That's right, carrying a gun increases the odds that you'll be shot by an armed assailant. It also increases the odds that you'll be shot fatally, by about 4.23 times. The authors interviewed 677 gun assault victims in Philadelphia, from between 2003 ........ Read more »
Branas, C., Richmond, T., Culhane, D., Ten Have, T., & Wiebe, D. (2009) Investigating the link between gun possession and gun assault. American Journal of Public Health. DOI: 10.2105/AJPH.2008.143099
- September 26, 2009
- 03:10 AM
- 587 views
Bees follow the crowd: Do whole-hive traits override individuals' genetics?
by Jeremy Yoder in Denim and Tweed
Social insects are often considered prototypes of group selection, in which the evolutionary interests of individual organisms are forced to defer to the needs of their social group. Now, the authors of a new study of honeybees argue that colony-level traits can override the genetic predispositions of individual bees [$-a].
.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px;........ Read more »
Linksvayer, T., Fondrk, M., & Page Jr., R. (2009) Honeybee social regulatory networks are shaped by colony-level selection. Am. Nat., 173(3). DOI: 10.1086/596527
Oldroyd, B., Smolenski, A., Cornuet, J., & Crozler, R. (1994) Anarchy in the beehive. Nature, 371(6500), 749. DOI: 10.1038/371749a0
Oxley, P., Thompson, G., & Oldroyd, B. (2008) Four quantitative trait loci that influence worker sterility in the honeybee (Apis mellifera). Genetics, 179(3), 1337-1343. DOI: 10.1534/genetics.108.087270
Page, R., & Fondrk, M. (1995) The effects of colony-level selection on the social organization of honey bee (Apis mellifera L.) colonies: colony-level components of pollen hoarding. Behavioral Ecol. , 36(2), 135-44. DOI: 10.1007/BF00170718
- September 17, 2009
- 12:05 PM
- 1,165 views
With or without you? Species interactions and responses to climate change
by Jeremy Yoder in Denim and Tweed
Reading a pair of papers recently published in PLoS ONE, you might be forgiven for thinking that ecologists don't know whether or not interactions between species matter. Both examine the effects of climate change on ecological communities -- but where one assumes that species in a community are as interchangeable as bricks in a wall, the other concludes that the presence of competitors is pretty important.
First, Stralberg et al. attempt to predict what will happen to the birds of California u........ Read more »
Adler, P., Leiker, J., & Levine, J. (2009) Direct and indirect effects of climate change on a prairie plant community. PLoS ONE, 4(9). DOI: 10.1371/journal.pone.0006887
Pelini, S., Dzurisin, J., Prior, K., Williams, C., Marsico, T., Sinclair, B., & Hellmann, J. (2009) Translocation experiments with butterflies reveal limits to enhancement of poleward populations under climate change. Proc. Nat. Acad. Sci. USA, 106(27), 11160-5. DOI: 10.1073/pnas.0900284106
Post, E., & Pedersen, C. (2008) Opposing plant community responses to warming with and without herbivores. Proc. Nat. Acad. Sci. USA, 105(34), 12353-8. DOI: 10.1073/pnas.0802421105
Stralberg, D., Jongsomjit, D., Howell, C., Snyder, M., Alexander, J., Wiens, J., & Root, T. (2009) Re-shuffling of species with climate disruption: A no-analog future for California birds?. PLoS ONE, 4(9). DOI: 10.1371/journal.pone.0006825
Visser, M., Holleman, L., & Gienapp, P. (2005) Shifts in caterpillar biomass phenology due to climate change and its impact on the breeding biology of an insectivorous bird. Oecologia, 147(1), 164-172. DOI: 10.1007/s00442-005-0299-6
- September 11, 2009
- 10:34 PM
- 1,453 views
Bat-eating tits!
by Jeremy Yoder in Denim and Tweed
Like pretty much anyone else writing about this, I'm in it for the headline. Well, maybe 30% for the headline -- this is also just freaky natural history. A paper in Biology Letters reports that great tits (Parus major -- basically big chickadees) will hunt and eat hibernating bats [$-a] if they can't find other food sources.
The paper reports on ten years of recorded bat-eating by a population of great tits in Hungary, capped by two years of systematic observations and a couple simple experime........ Read more »
Estok, P., Zsebok, S., & Siemers, B. (2009) Great tits search for, capture, kill and eat hibernating bats. Biology Letters. DOI: 10.1098/rsbl.2009.0611
- September 9, 2009
- 01:33 PM
- 1,049 views
The omnivores' solution: Tadpoles independently solve a common problem the same way
by Jeremy Yoder in Denim and Tweed
One of the key observations in support of evolutionary theory is that similar lifestyles can lead distantly-related living things to evolve strikingly similar traits. Compare an echidna and a hedgehog, distantly related mammals with very similar lifestyles. This kind of convergence can occur on much smaller scales of time and space, too, as a new paper just released online by Proceedings of the Royal Society shows. Its authors demonstrate that populations of spadefoot toads have independently ev........ Read more »
Pfennig, D., & Frankino, W. (1997) Kin-mediated morphogenesis in facultatively cannibalistic tadpoles. Evolution, 51(6), 1993. DOI: 10.2307/2411019
Rice, A., Leichty, A., & Pfennig, D. (2009) Parallel evolution and ecological selection: replicated character displacement in spadefoot toads. Proc. R. Soc. B. DOI: 10.1098/rspb.2009.1337
- August 21, 2009
- 12:10 PM
- 1,371 views
That possum you just ran over? It might have saved you from Lyme disease
by Jeremy Yoder in Denim and Tweed
Growing up in suburban Pennsylvania, where the most hazardous wildlife not extirpated from our woods is the occasional crazed whitetail deer, there was really only one danger I associated with the outdoors -- ticks. Specifically, ticks carrying Lyme disease, a not-very-pleasant bacterial infection that attacks the joints, heart, and nervous system if left untreated. According to a paper released online early in Proceedings of the Royal Society B, my risk of picking up Lyme disease on an excursio........ Read more »
Keesing, F., Holt, R., & Ostfeld, R. (2006) Effects of species diversity on disease risk. Ecology Letters, 9(4), 485-98. DOI: 10.1111/j.1461-0248.2006.00885.x
Keesing, F., Brunner, J., Duerr, S., Killilea, M., LoGiudice, K., Schmidt, K., Vuong, H., & Ostfeld, R. (2009) Hosts as ecological traps for the vector of Lyme disease. Proc. R. Soc. B. DOI: 10.1098/rspb.2009.1159
topics
join us!
Do you write about peer-reviewed research in your blog? Use ResearchBlogging.org to make it easy for your readers — and others from around the world — to find your serious posts about academic research.
If you don't have a blog, you can still use our site to learn about fascinating developments in cutting-edge research from around the world.
