Bio


I am interested in the evolution of insect morphology and ecology in deep time. I occasionally also study ticks, amphibians, and plants.

Honors & Awards


  • Snodgrass Memorial Research Award, Entomological Society of America (2017)
  • Graduate Student Hall of Fame, Mississippi State University (2016)
  • M.S. Graduate Research Assistant of the Year, Mississippi State University (2016)
  • Graduate Student Award for Excellence in Research, Mississippi State University (2016)
  • Best Student Oral Presentation, Australian Entomological Society (2015)
  • President's Prize, Entomological Society of America (2014)
  • Harry K. Clench Memorial Award, The Lepidopterists' Society (2014)
  • President's Prize for best student presentation, Entomological Society of America (2013)
  • Harry K. Clench Memorial Award, The Lepidopterists' Society (2013)
  • Undergraduate Student Achievement Award, Entomological Society of America (2013)
  • Judith K. Reed Commencement Award, University of Maryland (2013)

Stanford Advisors


All Publications


  • Wing patterns of ditrysian moths (Lepidoptera: Psychidae) include variants and violations of predictive models Austral Entomology Schachat, S. R., Brown, R. L. 2018

    View details for DOI 10.1111/aen.12284

  • Color patterning in hard ticks (Acari: Ixodidae) Journal of Medical Entomology Schachat, S. R., Robbins, R. G., Goddard, J. 2018

    View details for DOI 10.1093/jme/tjx173

  • The wing pattern of Moerarchis Durrant, 1914 (Lepidoptera: Tineidae) clarifies transitions between predictive models ROYAL SOCIETY OPEN SCIENCE Schachat, S. R. 2017; 4 (3)
  • Variable wing venation in Agathiphaga (Lepidoptera: Agathiphagidae) is key to understanding the evolution of basal moths ROYAL SOCIETY OPEN SCIENCE Schachat, S. R., Gibbs, G. 2016; 3 (10)
  • Forewing color pattern in Micropterigidae (Insecta: Lepidoptera): homologies between contrast boundaries, and a revised hypothesis for the origin of symmetry systems BMC EVOLUTIONARY BIOLOGY Schachat, S. R., Brown, R. L. 2016; 16

    Abstract

    Despite the great importance of lepidopteran wing patterns in various biological disciplines, homologies between wing pattern elements in different moth and butterfly lineages are still not understood. Among other reasons, this may be due to an incomplete understanding of the relationship between color pattern and wing venation; many individual wing pattern elements have a known relationship with venation, but a framework to unite all wing pattern elements with venation is lacking. Though plesiomorphic wing veins are known to influence color patterning even when not expressed in the adult wing, most studies of wing pattern evolution have focused on derived taxa with a reduced suite of wing veins.The present study aims to address this gap through an examination of Micropterigidae, a very early-diverged moth family in which all known plesiomorphic lepidopteran veins are expressed in the adult wing. The relationship between wing pattern and venation was examined in 66 species belonging to 9 genera. The relationship between venation and pattern element location, predicted based on moths in the family Tortricidae, holds for Sabatinca just as it does for Micropterix. However, the pattern elements that are lightly colored in Micropterix are dark in Sabatinca, and vice-versa. When plotted onto a hypothetical nymphalid wing in accordance with the relationship between pattern and venation discussed here, the wing pattern of Sabatinca doroxena very closely resembles the nymphalid groundplan.The color difference in pattern elements between Micropterix and Sabatinca indicates that homologies exist among the contrast boundaries that divide wing pattern elements, and that color itself is not a reliable indicator of homology. The similarity between the wing pattern of Sabatinca doroxena and the nymphalid groundplan suggests that the nymphalid groundplan may have originated from a Sabatinca-like wing pattern subjected to changes in wing shape and reduced expression of venation.

    View details for DOI 10.1186/s12862-016-0687-z

    View details for Web of Science ID 000376496600002

    View details for PubMedID 27230100

    View details for PubMedCentralID PMC4880886

  • Conservation threats and the phylogenetic utility of IUCN Red List rankings in Incilius toads CONSERVATION BIOLOGY Schachat, S. R., Mulcahy, D. G., Mendelson, J. R. 2016; 30 (1): 72-81

    Abstract

    Phylogenetic analysis of extinction threat is an emerging tool in the field of conservation. However, there are problems with the methods and data as commonly used. Phylogenetic sampling usually extends to the level of family or genus, but International Union for Conservation of Nature (IUCN) rankings are available only for individual species, and, although different species within a taxonomic group may have the same IUCN rank, the species may have been ranked as such for different reasons. Therefore, IUCN rank may not reflect evolutionary history and thus may not be appropriate for use in a phylogenetic context. To be used appropriately, threat-risk data should reflect the cause of extinction threat rather than the IUCN threat ranking. In a case study of the toad genus Incilius, with phylogenetic sampling at the species level (so that the resolution of the phylogeny matches character data from the IUCN Red List), we analyzed causes of decline and IUCN threat rankings by calculating metrics of phylogenetic signal (such as Fritz and Purvis' D). We also analyzed the extent to which cause of decline and threat ranking overlap by calculating phylogenetic correlation between these 2 types of character data. Incilius species varied greatly in both threat ranking and cause of decline; this variability would be lost at a coarser taxonomic resolution. We found far more phylogenetic signal, likely correlated with evolutionary history, for causes of decline than for IUCN threat ranking. Individual causes of decline and IUCN threat rankings were largely uncorrelated on the phylogeny. Our results demonstrate the importance of character selection and taxonomic resolution when extinction threat is analyzed in a phylogenetic context.

    View details for DOI 10.1111/cobi.12567

    View details for Web of Science ID 000368938000009

    View details for PubMedID 26243724

  • Attack risk for butterflies changes with eyespot number and size ROYAL SOCIETY OPEN SCIENCE Ho, S., Schachat, S. R., Piel, W. H., Monteiro, A. 2016; 3 (1)

    Abstract

    Butterfly eyespots are known to function in predator deflection and predator intimidation, but it is still unclear what factors cause eyespots to serve one function over the other. Both functions have been demonstrated in different species that varied in eyespot size, eyespot number and wing size, leaving the contribution of each of these factors to butterfly survival unclear. Here, we study how each of these factors contributes to eyespot function by using paper butterfly models, where each factor is varied in turn, and exposing these models to predation in the field. We find that the presence of multiple, small eyespots results in high predation, whereas single large eyespots (larger than 6 mm in diameter) results in low predation. These data indicate that single large eyespots intimidate predators, whereas multiple small eyespots produce a conspicuous, but non-intimidating signal to predators. We propose that eyespots may gain an intimidation function by increasing in size. Our measurements of eyespot size in 255 nymphalid butterfly species show that large eyespots are relatively rare and occur predominantly on ventral wing surfaces. By mapping eyespot size on the phylogeny of the family Nymphalidae, we show that these large eyespots, with a potential intimidation function, are dispersed throughout multiple nymphalid lineages, indicating that phylogeny is not a strong predictor of eyespot size.

    View details for DOI 10.1098/rsos.150614

    View details for Web of Science ID 000377968600031

    View details for PubMedID 26909190

    View details for PubMedCentralID PMC4736945

  • Insect herbivory from early Permian Mitchell Creek Flats of north-central Texas: Opportunism in a balanced component community PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY Schachat, S. R., Labandeira, C. C., Chaney, D. S. 2015; 440: 830-847
  • Color Pattern on the Forewing of Micropterix (Lepidoptera: Micropterigidae): Insights into the Evolution of Wing Pattern and Wing Venation in Moths PLOS ONE Schachat, S. R., Brown, R. L. 2015; 10 (10)

    Abstract

    Wing patterns are key taxonomic characters that have long been used in descriptions of Lepidoptera; however, wing pattern homologies are not understood among different moth lineages. Here, we examine the relationship between wing venation and wing pattern in the genus Micropterix, among the most basal extant Lepidoptera, in order to evaluate the two existing predictive models that have the potential to establish wing pattern element homologies for the order. The location of wing pattern elements along the costal margin of the wing in Micropterix is consistent with the predictions of the model proposed for Tortricidae by Brown and Powell in 1991, later modified by Baixeras in 2002. The predictive power of this model for such distantly related taxa suggests that the model may hold across various superfamilies within Lepidoptera, and supports the long-held notion that fasciae, not spots, are the most likely primitive wing pattern elements for the order. In addition, the location of wing pattern elements suggests that the wing vein commonly termed Sc1 may in fact be a different vein, which Comstock identified in Trichoptera and referred to as "a."

    View details for DOI 10.1371/journal.pone.0139972

    View details for Web of Science ID 000362499200067

    View details for PubMedID 26437004

    View details for PubMedCentralID PMC4593546

  • Evolution of a complex behavior: the origin and initial diversification of foliar galling by Permian insects SCIENCE OF NATURE Schachat, S. R., Labandeira, C. C. 2015; 102 (3-4)

    Abstract

    A central notion of the early evolution of insect galling is that this unique behavior was uncommon to rare before the diversification of angiosperms 135 to 125 m.yr. ago. However, evidence accumulated during recent years shows that foliar galls were diverse and locally abundant as early as the Permian Period, 299 to 252 m.yr. ago. In particular, a diversity of leaf galling during the Early Permian has recently been documented by the plant-damage record of foliar galls and, now, our interpretation of the body-fossil record of culprit insect gallers. Small size is a prerequisite for gallers. Wing-length measurements of Permian insects indicate that several small-bodied hemipteroid lineages originated early during the Permian, some descendant lineages of which gall the leaves of seed plants to the present day. The earliest foliar gallers likely were Protopsyllidiidae (Hemiptera) and Lophioneuridae (Thripida). Much of the Early Permian was a xeric interval, and modern galls are most common in dry, extra-tropical habitats such as scrubland and deserts. Plant-damage, insect body fossils, and the paleoclimate record collectively support the ecological expansion of foliar galling during the Early Permian and its continued expansion through the Late Permian.

    View details for DOI 10.1007/s00114-015-1266-7

    View details for Web of Science ID 000355942200002

    View details for PubMedID 25783809

  • Nymphalid eyespots are co-opted to novel wing locations following a similar pattern in independent lineages BMC EVOLUTIONARY BIOLOGY Schachat, S. R., Oliver, J. C., Monteiro, A. 2015; 15

    Abstract

    Variation in the number of repeated traits, or serial homologs, has contributed greatly to animal body plan diversity. Eyespot color patterns of nymphalid butterflies, like arthropod and vertebrate limbs, are an example of serial homologs. These eyespot color patterns originated in a small number of wing sectors on the ventral hindwing surface and later appeared in novel wing sectors, novel wings, and novel wing surfaces. However, the details of how eyespots were co-opted to these novel wing locations are currently unknown.We used a large data matrix of eyespot/presence absence data, previously assembled from photographs of contemporary species, to perform a phylogenetic investigation of eyespot origins in nine independent nymphalid lineages. To determine how the eyespot gene regulatory network acquired novel positional information, we used phylogenetic correlation analyses to test for non-independence in the origination of eyespots. We found consistent patterns of eyespot gene network redeployment in the nine lineages, where eyespots first redeployed from the ventral hindwing to the ventral forewing, then to new sectors within the ventral wing surface, and finally to the dorsal wing surface. Eyespots that appeared in novel wing sectors modified the positional information of their serial homolog ancestors in one of two ways: by changing the wing or surface identity while retaining sector identity, or by changing the sector identity while retaining wing and surface identity.Eyespot redeployment to novel sectors, wings, and surfaces happened multiple times in different nymphalid subfamilies following a similar pattern. This indicates that parallel mutations altering expression of the eyespot gene regulatory network led to its co-option to novel wing locations over time.

    View details for DOI 10.1186/s12862-015-0300-x

    View details for Web of Science ID 000350061900002

    View details for PubMedID 25886182

    View details for PubMedCentralID PMC4335541

  • Insect biodiversity in Meiji and Art Nouveau design American Entomologist Schachat, S. R. 2015; 61 (4): 215-222

    View details for DOI 10.1093/ae/tmv071

  • PLANT-INSECT INTERACTIONS FROM EARLY PERMIAN (KUNGURIAN) COLWELL CREEK POND, NORTH-CENTRAL TEXAS: THE EARLY SPREAD OF HERBIVORY IN RIPARIAN ENVIRONMENTS INTERNATIONAL JOURNAL OF PLANT SCIENCES Schachat, S. R., Labandeira, C. C., Gordon, J., Chaney, D., Levi, S., Halthore, M. N., Alvarez, J. 2014; 175 (8): 855-890

    View details for DOI 10.1086/677679

    View details for Web of Science ID 000343226300001

  • Drawn before Wonderland: Bizarre illustrated insects of the nineteenth century American Entomologist Schachat, S. R. 2014; 60 (3): 162-165

    View details for DOI 10.1093/ae/60.3.162