Molly Cummings | The University of Texas at Austin (original) (raw)
Papers by Molly Cummings
Science (New York, N.Y.), Nov 20, 2015
Despite appearing featureless to our eyes, the open ocean is a highly variable environment for po... more Despite appearing featureless to our eyes, the open ocean is a highly variable environment for polarization-sensitive viewers. Dynamic visual backgrounds coupled with predator encounters from all possible directions make this habitat one of the most challenging for camouflage. We tested open-ocean crypsis in nature by collecting more than 1500 videopolarimetry measurements from live fish from distinct habitats under a variety of viewing conditions. Open-ocean fish species exhibited camouflage that was superior to that of both nearshore fish and mirrorlike surfaces, with significantly higher crypsis at angles associated with predator detection and pursuit. Histological measurements revealed that specific arrangements of reflective guanine platelets in the fish's skin produce angle-dependent polarization modifications for polarocrypsis in the open ocean, suggesting a mechanism for natural selection to shape reflectance properties in this complex environment.
Ecology and Evolution
Social interactions can drive distinct gene expression profiles which may vary by social context.... more Social interactions can drive distinct gene expression profiles which may vary by social context. Here we use female sailfin molly fish (Poecilia latipinna) to identify genomic profiles associated with preference behavior in distinct social contexts: male interactions (mate choice) versus female interactions (shoaling partner preference). We measured the behavior of 15 females interacting in a non‐contact environment with either two males or two females for 30 min followed by whole‐brain transcriptomic profiling by RNA sequencing. We profiled females that exhibited high levels of social affiliation and great variation in preference behavior to identify an order of magnitude more differentially expressed genes associated with behavioral variation than by differences in social context. Using a linear model (limma), we took advantage of the individual variation in preference behavior to identify unique gene sets that exhibited distinct correlational patterns of expression with preferen...
The American Naturalist, 2012
Proceedings of the National Academy of Sciences, 2009
It is commonly assumed that natural selection imposed by predators is the prevailing force drivin... more It is commonly assumed that natural selection imposed by predators is the prevailing force driving the evolution of aposematic traits. Here, we demonstrate that aposematic signals are shaped by sexual selection as well. We evaluated sexual selection for coloration brightness in populations of the poison frog Oophaga [Dendrobates] pumilio in Panama's Bocas del Toro archipelago. We assessed female preferences for brighter males by manipulating the perceived brightness of spectrally matched males in two-way choice experiments. We found strong female preferences for bright males in two island populations and weaker or ambiguous preferences in females from mainland populations. Spectral reflectance measurements, coupled with an O. pumilio -specific visual processing model, showed that O. pumilio coloration was significantly brighter in island than in mainland morphs. In one of the island populations (Isla Solarte), males were significantly more brightly colored than females. Taken to...
Journal of Biogeography, 2010
The American Naturalist, 2010
Animal cognition, 2018
The relationship between an individual's cognitive abilities and other behavioural attributes... more The relationship between an individual's cognitive abilities and other behavioural attributes is complex, yet critical to understanding how individual differences in cognition arise. Here we use western mosquitofish, Gambusia affinis, to investigate the relationship between individual associative learning performance in numerical discrimination tests and independent measures of activity, exploration, anxiety and sociability. We found extensive and highly repeatable inter-individual variation in learning performance (r = 0.89; ICC = 0.89). Males and females exhibited similar learning performance, yet differed in sociability, activity and their relationship between learning and anxiety/exploration tendencies. Sex-specific multivariate behaviour scores successfully predicted variation in individual learning performance, whereas combined sex analyses did not. Female multivariate behaviour scores significantly predict learning performance across females (ρ = 0.80, p = 0.005) with hig...
Journal of the Royal Society, Interface / the Royal Society, Jan 6, 2015
Predator evasion in the open ocean is difficult because there are no objects to hide behind. The ... more Predator evasion in the open ocean is difficult because there are no objects to hide behind. The silvery surface of fish plays an important role in open water camouflage. Various models have been proposed to account for the broadband reflectance by the fish skin that involve one-dimensional variations in the arrangement of guanine crystal reflectors, yet the three-dimensional organization of these guanine platelets have not been well characterized. Here, we report the three-dimensional organization and the optical properties of integumentary guanine platelets in a silvery marine fish, the lookdown (Selene vomer). Our structural analysis and computational modelling show that stacks of guanine platelets with random yaw angles in the fish skin produce broadband reflectance via colour mixing. Optical axes of the guanine platelets and the collagen layer are aligned closely and provide bulk birefringence properties that influence the polarization reflectance by the skin. These data demons...
Nature, 2006
Batesian mimicry-resemblance of a toxic model by an edible mimic-depends on deceiving predators. ... more Batesian mimicry-resemblance of a toxic model by an edible mimic-depends on deceiving predators. Mimetic advantage is considered to be dependent on frequency because an increase in mimic abundance leads to breakdown of the warning signal. Where multiple toxic species are available, batesian polymorphism is predicted-that is, mimics diversify to match sympatric models. Despite the prevalence of batesian mimicry in nature,
Science (New York, N.Y.), Jan 20, 2015
Despite appearing featureless to our eyes, the open ocean is a highly variable environment for po... more Despite appearing featureless to our eyes, the open ocean is a highly variable environment for polarization-sensitive viewers. Dynamic visual backgrounds coupled with predator encounters from all possible directions make this habitat one of the most challenging for camouflage. We tested open-ocean crypsis in nature by collecting more than 1500 videopolarimetry measurements from live fish from distinct habitats under a variety of viewing conditions. Open-ocean fish species exhibited camouflage that was superior to that of both nearshore fish and mirrorlike surfaces, with significantly higher crypsis at angles associated with predator detection and pursuit. Histological measurements revealed that specific arrangements of reflective guanine platelets in the fish's skin produce angle-dependent polarization modifications for polarocrypsis in the open ocean, suggesting a mechanism for natural selection to shape reflectance properties in this complex environment.
Evolution, 2005
Trinidad guppies (Poecilia reticulata) are distributed along an environmental gradient in caroten... more Trinidad guppies (Poecilia reticulata) are distributed along an environmental gradient in carotenoid avail- ability that limits the carotenoid content of the orange spots of males. The amount of synthetic red pteridines (dro- sopterins) in the orange spots covaries with the carotenoid content, such that the ratio of the two types of pigments is roughly conserved across streams. Carotenoids and drosopterins
Proceedings of The National Academy of Sciences, 2006
Many animals advertise their chemical defense to predators with conspicuous coloration and unpala... more Many animals advertise their chemical defense to predators with conspicuous coloration and unpalatability, but little is known about the information in these signal elements. To effectively avoid predation, is it more advantageous to invest in increased conspicuousness or greater noxiousness, or to allocate equally to both signal modalities? Using natural variation among poison frog species measured with spectral reflectance and
Science (New York, N.Y.), Nov 20, 2015
Despite appearing featureless to our eyes, the open ocean is a highly variable environment for po... more Despite appearing featureless to our eyes, the open ocean is a highly variable environment for polarization-sensitive viewers. Dynamic visual backgrounds coupled with predator encounters from all possible directions make this habitat one of the most challenging for camouflage. We tested open-ocean crypsis in nature by collecting more than 1500 videopolarimetry measurements from live fish from distinct habitats under a variety of viewing conditions. Open-ocean fish species exhibited camouflage that was superior to that of both nearshore fish and mirrorlike surfaces, with significantly higher crypsis at angles associated with predator detection and pursuit. Histological measurements revealed that specific arrangements of reflective guanine platelets in the fish's skin produce angle-dependent polarization modifications for polarocrypsis in the open ocean, suggesting a mechanism for natural selection to shape reflectance properties in this complex environment.
Ecology and Evolution
Social interactions can drive distinct gene expression profiles which may vary by social context.... more Social interactions can drive distinct gene expression profiles which may vary by social context. Here we use female sailfin molly fish (Poecilia latipinna) to identify genomic profiles associated with preference behavior in distinct social contexts: male interactions (mate choice) versus female interactions (shoaling partner preference). We measured the behavior of 15 females interacting in a non‐contact environment with either two males or two females for 30 min followed by whole‐brain transcriptomic profiling by RNA sequencing. We profiled females that exhibited high levels of social affiliation and great variation in preference behavior to identify an order of magnitude more differentially expressed genes associated with behavioral variation than by differences in social context. Using a linear model (limma), we took advantage of the individual variation in preference behavior to identify unique gene sets that exhibited distinct correlational patterns of expression with preferen...
The American Naturalist, 2012
Proceedings of the National Academy of Sciences, 2009
It is commonly assumed that natural selection imposed by predators is the prevailing force drivin... more It is commonly assumed that natural selection imposed by predators is the prevailing force driving the evolution of aposematic traits. Here, we demonstrate that aposematic signals are shaped by sexual selection as well. We evaluated sexual selection for coloration brightness in populations of the poison frog Oophaga [Dendrobates] pumilio in Panama's Bocas del Toro archipelago. We assessed female preferences for brighter males by manipulating the perceived brightness of spectrally matched males in two-way choice experiments. We found strong female preferences for bright males in two island populations and weaker or ambiguous preferences in females from mainland populations. Spectral reflectance measurements, coupled with an O. pumilio -specific visual processing model, showed that O. pumilio coloration was significantly brighter in island than in mainland morphs. In one of the island populations (Isla Solarte), males were significantly more brightly colored than females. Taken to...
Journal of Biogeography, 2010
The American Naturalist, 2010
Animal cognition, 2018
The relationship between an individual's cognitive abilities and other behavioural attributes... more The relationship between an individual's cognitive abilities and other behavioural attributes is complex, yet critical to understanding how individual differences in cognition arise. Here we use western mosquitofish, Gambusia affinis, to investigate the relationship between individual associative learning performance in numerical discrimination tests and independent measures of activity, exploration, anxiety and sociability. We found extensive and highly repeatable inter-individual variation in learning performance (r = 0.89; ICC = 0.89). Males and females exhibited similar learning performance, yet differed in sociability, activity and their relationship between learning and anxiety/exploration tendencies. Sex-specific multivariate behaviour scores successfully predicted variation in individual learning performance, whereas combined sex analyses did not. Female multivariate behaviour scores significantly predict learning performance across females (ρ = 0.80, p = 0.005) with hig...
Journal of the Royal Society, Interface / the Royal Society, Jan 6, 2015
Predator evasion in the open ocean is difficult because there are no objects to hide behind. The ... more Predator evasion in the open ocean is difficult because there are no objects to hide behind. The silvery surface of fish plays an important role in open water camouflage. Various models have been proposed to account for the broadband reflectance by the fish skin that involve one-dimensional variations in the arrangement of guanine crystal reflectors, yet the three-dimensional organization of these guanine platelets have not been well characterized. Here, we report the three-dimensional organization and the optical properties of integumentary guanine platelets in a silvery marine fish, the lookdown (Selene vomer). Our structural analysis and computational modelling show that stacks of guanine platelets with random yaw angles in the fish skin produce broadband reflectance via colour mixing. Optical axes of the guanine platelets and the collagen layer are aligned closely and provide bulk birefringence properties that influence the polarization reflectance by the skin. These data demons...
Nature, 2006
Batesian mimicry-resemblance of a toxic model by an edible mimic-depends on deceiving predators. ... more Batesian mimicry-resemblance of a toxic model by an edible mimic-depends on deceiving predators. Mimetic advantage is considered to be dependent on frequency because an increase in mimic abundance leads to breakdown of the warning signal. Where multiple toxic species are available, batesian polymorphism is predicted-that is, mimics diversify to match sympatric models. Despite the prevalence of batesian mimicry in nature,
Science (New York, N.Y.), Jan 20, 2015
Despite appearing featureless to our eyes, the open ocean is a highly variable environment for po... more Despite appearing featureless to our eyes, the open ocean is a highly variable environment for polarization-sensitive viewers. Dynamic visual backgrounds coupled with predator encounters from all possible directions make this habitat one of the most challenging for camouflage. We tested open-ocean crypsis in nature by collecting more than 1500 videopolarimetry measurements from live fish from distinct habitats under a variety of viewing conditions. Open-ocean fish species exhibited camouflage that was superior to that of both nearshore fish and mirrorlike surfaces, with significantly higher crypsis at angles associated with predator detection and pursuit. Histological measurements revealed that specific arrangements of reflective guanine platelets in the fish's skin produce angle-dependent polarization modifications for polarocrypsis in the open ocean, suggesting a mechanism for natural selection to shape reflectance properties in this complex environment.
Evolution, 2005
Trinidad guppies (Poecilia reticulata) are distributed along an environmental gradient in caroten... more Trinidad guppies (Poecilia reticulata) are distributed along an environmental gradient in carotenoid avail- ability that limits the carotenoid content of the orange spots of males. The amount of synthetic red pteridines (dro- sopterins) in the orange spots covaries with the carotenoid content, such that the ratio of the two types of pigments is roughly conserved across streams. Carotenoids and drosopterins
Proceedings of The National Academy of Sciences, 2006
Many animals advertise their chemical defense to predators with conspicuous coloration and unpala... more Many animals advertise their chemical defense to predators with conspicuous coloration and unpalatability, but little is known about the information in these signal elements. To effectively avoid predation, is it more advantageous to invest in increased conspicuousness or greater noxiousness, or to allocate equally to both signal modalities? Using natural variation among poison frog species measured with spectral reflectance and