Ecology: tribal warfare maintains microbial diversity

When two tribes of Myxococcus bacteria attack each other, the most numerous usually wins. Established colonies can therefore resist invaders by outnumbering them. This shows how positive frequency dependence can maintain diversity across spatially structured environments

Mimicry in Insects: An Illustrated Study in Mimicry and Cryptic Coloration in Insects

INSECT MIMICRY 4 WHAT IS MIMICRY? 5 MÜLLERIAN MIMICRY 7 MÜLLERIAN MIMICRY 8 YELLOWJACKET – VESPULA SPP. 9 HONEY BEE – APIS SPP. 10 BUMBLE BEE – BOMBUS SPP. 11 VELVET ANT (COW KILLER) – DASYMUTILLA OCCIDENTALIS 12 BLISTER BEETLE – EUPOMPHA ELEGANS 13 THREAD-WAISTED WASP – AMMOPHILA SPP. 14 MONARCH BUTTERFLY – DANAUS PLEXIPPUS 15 VICEROY BUTTERFLY – LIMENTIS SPP. 16 BATESIAN MIMICRY 17 BATESIAN MIMICRY 18 METALLIC WOODBORING BEETLE – ACMAEODERA SPP. 19 WASP BEETLE – CLYTUS SPP. 20 FLOWER LONGHORN BEETLE – TYPOCERUS SPP. 21 BEE BEETLE – TRICHIUS SPP. 22 BEE FLY – BOMBYLIUS SPP. 23 DRONE FLY – ERISTALIS SPP. 24 HOVER FLY –EUPEODES SPP. 25 TACHINID FLY – CYLINDROMYIA SPP. 26 SNOWBERRY CLEARWING MOTH – HEMARIS DIFFINIS 27 AMERICAN HORNET MOTH – SESIA SPP. 28 CRYPTIC COLORATION & CAMOUFLAGE 29 CRYPTIC COLORATION & CAMOUFLAGE 30 SPHINX MOTH (SNAKE CATERPILLAR) – HEMEROPLANES TRIPTOLEMUS 32 COMMON LYTROSIS MOTH – LYTROSIS UNITARIA 33 KATYDID (LEAF BUG) – MICROCENTRUM RHOMBIFOLIUM 34 STICK INSECT – PHASMIDS 35 THORN BUG – UMBONIA CRASSICORNIS 36 FLOWER MANTID – HYMENOPUS CORONATUS 37 REFERENCES 3

Selection on the wing in Heliconius butterflies

<p>Asbtract</p> <p>To what extent population structure favours the establishment of new phenotypes within a species remains a fundamental question in evolutionary studies. By reducing gene flow, habitat fragmentation is a major factor shaping the genetic structuring of populations, favouring isolation of small populations in which drift may rapidly change frequencies of new variants. When these variants provide advantages to individuals, the combined effect of selection and drift can lead to rapid shifts in phenotypes. In a study published in <it>BMC Genetics</it>, Albuquerque de Moura <it>et al. </it>asked whether such a general pattern of population structure can be observed in <it>Heliconius </it>species, which could have strong implication in the evolution of colour pattern diversification in these butterflies. In this commentary we discuss the potential roles of these three processes (drift, selection and dispersal) on the evolution of <it>Heliconius </it>wing patterns in regard to the findings of a common fine-scale population structure within the co-mimetic species <it>H. melpomene </it>and <it>H. erato</it>. Indeed, a general pattern of population subdivision in the history of these two species may have provoked the major phenotypical shifts observed in their wing colour patterns. The suggestion that coupled environmental pressures (counter-selection of dispersal and selection on co-evolved traits) could be responsible for identical genetic differentiation profiles in <it>H. erato </it>and <it>H. melpomene </it>clearly merits further investigations using both detailed population genetic (including landscape genetic) and ecological studies.</p

Modeling the Evolution of Mimicry

A novel agent based, artificial life model, for the evolution of mimicry is presented. This model is a predator-prey co-evolution scenario where pattern representation phenotype is simulated with Cellular Automata, while behaviors of pattern recognition is configured with Hopfield Network. A visual three dimensional toroidal cube is used to construct a universe in which agents have complete freedom of mobility, genetic representation of behavior and reproduction capability to evolve new behaviors in successive generations. These agents are classified into categories of predator and prey species. Genome of prey species control their mobility and palatability, while 2D Cellular Automata (CA) is used to represent a pattern, where the rule to generate the CA is also genetically represented. Through evolution, successive generations of prey species develop new patterns to represent them both visually and to the predators. Predators are agents with the primary purpose of providing selection pressure for the evolution of mimicry. They are equipped with Hopfield Network memory to recognize new CA pattern and make intelligent decisions to consume the prey based on their level of palatability. Using the above construction of ideas, successful emulation of the natural process of mimicry is achieved. Also complex behavior pattern of Batesian and Mullerian mimicry is simulated and studied

Cognitive dimensions of predator responses to imperfect mimicry?

Many palatable insects, for example hoverflies, deter predators by mimicking well-defended insects such as wasps. However, for human observers, these flies often seem to be little better than caricatures of wasps &#x2013; their visual appearance and behaviour are easily distinguishable. This imperfect mimicry baffles evolutionary biologists, because one might expect natural selection to do a more thorough job. Here we discuss two types of cognitive processes that might explain why mimics distinguishable mimics might enjoy increased protection from predation. Speed accuracy tradeoffs in predator decision making might give imperfect mimics sufficient time to escape, and predators under time constraint might avoid time-consuming discriminations between well-defended models and inaccurate edible mimics, and instead adopt a &#x201c;safety first&#x201d; policy of avoiding insects with similar appearance. Categorization of prey types by predators could mean that wholly dissimilar mimics may be protected, provided they share some common property with noxious prey

EST analysis of male accessory glands from Heliconius butterflies with divergent mating systems

<p>Abstract</p> <p>Background</p> <p><it>Heliconius </it>butterflies possess a remarkable diversity of phenotypes, physiologies, and behaviors that has long distinguished this genus as a focal taxon in ecological and evolutionary research. Recently <it>Heliconius </it>has also emerged as a model system for using genomic methods to investigate the causes and consequences of biological diversity. One notable aspect of <it>Heliconius </it>diversity is a dichotomy in mating systems which provides an unusual opportunity to investigate the relationship between sexual selection and the evolution of reproductive proteins. As a first step in pursuing this research, we report the generation and analysis of expressed sequence tags (ESTs) from the male accessory gland of <it>H. erato </it>and <it>H. melpomene</it>, species representative of the two mating systems present in the genus <it>Heliconius</it>.</p> <p>Results</p> <p>We successfully sequenced 933 ESTs clustering into 371 unigenes from <it>H. erato </it>and 1033 ESTs clustering into 340 unigenes from <it>H. melpomene</it>. Results from the two species were very similar. Approximately a third of the unigenes showed no significant BLAST similarity (E-value <10^-5) to sequences in GenBank's non-redundant databases, indicating that a large proportion of novel genes are expressed in <it>Heliconius </it>male accessory glands. In both species only a third of accessory gland unigenes were also found among genes expressed in wing tissue. About 25% of unigenes from both species encoded secreted proteins. This includes three groups of highly abundant unigenes encoding repetitive proteins considered to be candidate seminal fluid proteins; proteins encoded by one of these groups were detected in <it>H. erato </it>spermatophores.</p> <p>Conclusion</p> <p>This collection of ESTs will serve as the foundation for the future identification and evolutionary analysis of male reproductive proteins in <it>Heliconius </it>butterflies. These data also represent a significant advance in the rapidly growing collection of genomic resources available in <it>Heliconius </it>butterflies. As such, they substantially enhance this taxon as a model system for investigating questions of ecological, phenotypic, and genomic diversity.</p

Investigating candidate genes for an association with skin color pattern in the mimic poison frog Ranitomeya imitator

Understanding the genetic basis of adaptive traits can help us better understand their evolution. The mimic poison frog, Ranitomeya imitator, is native to Peru. Like many other species of poison frogs, it has aposematic coloration to warn predators of its toxicity, so that its dorsal color pattern is directly linked to its survival. Recently, R. imitator has undergone a mimetic radiation, in which it has evolved to mimic three species of congeneric poison frogs. This mimicry has caused a divergence of color pattern within R. imitator, giving rise to four different color pattern morphs (striped, spotted, banded, and varadero). In this thesis, the main objective is to investigate the genetic basis of this phenotypic divergence. Here, we focus specifically on investigating candidate color pattern genes in the striped and banded morphs, which differ mainly in their dorsal color (yellow to orange), hindlimb color (green to orange), and their dorsal pattern (striped to banded). To do this, we formed a lab-reared pedigree by crossing two morphs of R. imitator (striped and banded) for two generations. For each individual in the pedigree, we amplified each candidate gene (asip, mc1r, bsn, and retsat) and sequenced them via Sanger sequencing. To determine phenotypes, we took spectral reflectance measurements and photos of each frog. We analyzed and summarized spectral reflectance data using the PAVO package in R. The photos were analyzed using a program written by Tyler Linderoth, which quantifies the orientation of the dorsal stripes/bands. We used the program Merlin to test for a genotype-phenotype association. Our tests indicated associations between genotype and color pattern phenotypes for all four candidate genes tested. Our results show that these genes are promising candidates for controlling aspects of skin color pattern in R. imitator. Further study of these genes will help elucidate the proximate mechanisms of phenotypic divergence in R. imitator, giving us a better understanding of the evolution of aposematism in this species and potential insights into the molecular basis of skin color pattern more generally

The diversification of Heliconius butterflies: what have we learned in 150 years?

Research into Heliconius butterflies has made a significant contribution to evolutionary biology. Here, we review our understanding of the diversification of these butterflies, covering recent advances and a vast foundation of earlier work. Whereas no single group of organisms can be sufficient for understanding life's diversity, after years of intensive study, research into Heliconius has addressed a wide variety of evolutionary questions. We first discuss evidence for widespread gene flow between Heliconius species and what this reveals about the nature of species. We then address the evolution and diversity of warning patterns, both as the target of selection and with respect to their underlying genetic basis. The identification of major genes involved in mimetic shifts, and homology at these loci between distantly related taxa, has revealed a surprising predictability in the genetic basis of evolution. In the final sections, we consider the evolution of warning patterns, and Heliconius diversity more generally, within a broader context of ecological and sexual selection. We consider how different traits and modes of selection can interact and influence the evolution of reproductive isolation.RMM is funded by a Junior Research Fellowship at King’s College, Cambridge. KMK is supported by the Balfour Studentship, University of Cambridge, SHMa by a Research Fellowship at St John's College, Cambridge, and SHMo by a Research Fellowship from the Royal Commission for the Exhibition of 1851. Our work on Heliconius has been additionally supported by the Agence Nationale de la Recherche (France), the Biology and Biotechnology Research Council (UK), the British Ecological Society, the European Research Council, the Natural Environment Research Council (UK), and the Smithsonian Tropical Research Institute.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/jeb.1267

The Influence of Flower Color on the Foraging Selection of the Julia Butterfly, Dyras Uilia, in a Captive Habitat at the Minnesota Zoo

https://openriver.winona.edu/urc2018/1006/thumbnail.jp