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1. Herbarium specimens reveal herbivory patterns across the genus Cucurbita

   https://doi.org/2021.2007.2021.452357  

   Jenny, L.A.; Shapiro, L.R.; Davis, C.C.; Davies, T.J.; Pierce, N.E.; Meineke, E. (July 2021, bioRxiv)

   PREMISE Quantifying how closely related plant species differ in susceptibility to insect herbivory is important for our understanding of variation in plant-insect ecological interactions and evolutionary pressures on plant functional traits. However, empirically measuring in situ variation in herbivory over the entire geographic range where a plant-insect complex occurs is logistically difficult. Recently, new methods have been developed to use herbarium specimens to investigate patterns in plant-insect interactions across geographic areas, and during periods of accelerating anthropogenic change. Such investigations can provide insights into changes in herbivory intensity and phenology in plants that are of ecological and agricultural importance. METHODS Here, we analyze 274 pressed herbarium samples from all 14 species in the economically important plant genus Cucurbita (Cucurbitaceae) to investigate variation in herbivory damage. This collection is comprised of specimens of wild, undomesticated Cucurbita that were collected from across their native range in the Neotropics and subtropics, and Cucurbita cultivars that were collected from both within their native range and from locations where they have been introduced for agriculture in temperate Eastern North America. RESULTS We find that herbivory is common on individuals of all Cucurbita species collected from throughout their geographic ranges; however, estimates of herbivory varied considerably among individuals, with greater damage observed in specimens collected from unmanaged habitat. We also find evidence that mesophytic species accrue more insect damage than xerophytic species. CONCLUSIONS Our study demonstrates that herbarium specimens are a useful resource for understanding ecological interactions between domesticated crop plants and co-evolved insect herbivores. 

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2. Herbarium specimens reveal herbivory patterns across the genus Cucurbita

   https://doi.org/10.1101/2021.07.21.452357  

   Jenny, L.A.; Shapiro, L.R.; Davis, C.C.; Davies, T.J.; Pierce, N.E.; and Meineke, E. (July 2021, bioRxiv)

   PREMISE Quantifying how closely related plant species differ in susceptibility to insect herbivory is important for our understanding of variation in plant-insect ecological interactions and evolutionary pressures on plant functional traits. However, empirically measuring in situ variation in herbivory over the entire geographic range where a plant-insect complex occurs is logistically difficult. Recently, new methods have been developed to use herbarium specimens to investigate patterns in plant-insect interactions across geographic areas, and during periods of accelerating anthropogenic change. Such investigations can provide insights into changes in herbivory intensity and phenology in plants that are of ecological and agricultural importance. METHODS Here, we analyze 274 pressed herbarium samples from all 14 species in the economically important plant genus Cucurbita (Cucurbitaceae) to investigate variation in herbivory damage. This collection is comprised of specimens of wild, undomesticated Cucurbita that were collected from across their native range in the Neotropics and subtropics, and Cucurbita cultivars that were collected from both within their native range and from locations where they have been introduced for agriculture in temperate Eastern North America. RESULTS We find that herbivory is common on individuals of all Cucurbita species collected from throughout their geographic ranges; however, estimates of herbivory varied considerably among individuals, with greater damage observed in specimens collected from unmanaged habitat. We also find evidence that mesophytic species accrue more insect damage than xerophytic species. CONCLUSIONS Our study demonstrates that herbarium specimens are a useful resource for understanding ecological interactions between domesticated crop plants and co-evolved insect herbivores. 

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3. Seeing herbaria in a new light: leaf reflectance spectroscopy unlocks trait and classification modeling in plant biodiversity collections

   https://doi.org/10.1111/nph.70357  

   White, Dawson M; Cavender‐Bares, Jeannine; Davis, Charles C; Guzmán_Q, J Antonio; Kothari, Shan; Robles, Jorge M; Meireles, José Eduardo (July 2025, New Phytologist)

   Summary Reflectance spectroscopy is a rapid method for estimating traits and discriminating species. Spectral libraries from herbarium specimens represent an untapped resource for generating broad phenomic datasets across space, time, and taxa.We conducted a proof‐of‐concept study using trait data and spectra from herbarium specimens up to 179 yr old, alongside data from recently dried and pressed leaves. We validated model accuracy and transferability for trait prediction and taxonomic discrimination.Trait models from herbarium spectra predicted leaf mass per area (LMA) withR² = 0.94 and %RMSE = 4.86%. Models for LMA prediction were transferable between herbarium and pressed spectra, achievingR² = 0.88, %RMSE = 8.76% for herbarium to pressed spectra, andR² = 0.76, %RMSE = 10.5% for the reverse transfer. Discriminant models classified leaf spectra from 25 species with 74% accuracy, and classification probabilities were significantly associated with several herbarium specimen quality metrics.The results validate herbarium spectral data for trait prediction and taxonomic discrimination, and demonstrate that trait modeling can benefit from the complementary use of pressed‐leaf and herbarium‐leaf spectral datasets. These promising advancements help to justify the spectral digitization of plant biodiversity collections and support their application in broad ecological and evolutionary investigations. 

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4. The acquisitive–conservative axis of leaf trait variation emerges even in homogeneous environments

   https://doi.org/10.1093/aob/mcaa198  

   Gorné, Lucas D; Díaz, Sandra; Minden, Vanessa; Onoda, Yusuke; Kramer, Koen; Muir, Christopher; Michaletz, Sean T; Lavorel, Sandra; Sharpe, Joanne; Jansen, Steven; et al (November 2020, Annals of Botany)

   Abstract Background and Aims The acquisitive–conservative axis of plant ecological strategies results in a pattern of leaf trait covariation that captures the balance between leaf construction costs and plant growth potential. Studies evaluating trait covariation within species are scarcer, and have mostly dealt with variation in response to environmental gradients. Little work has been published on intraspecific patterns of leaf trait covariation in the absence of strong environmental variation. Methods We analysed covariation of four leaf functional traits [specific leaf area (SLA) leaf dry matter content (LDMC), force to tear (Ft) and leaf nitrogen content (Nm)] in six Poaceae and four Fabaceae species common in the dry Chaco forest of Central Argentina, growing in the field and in a common garden. We compared intraspecific covariation patterns (slopes, correlation and effect size) of leaf functional traits with global interspecific covariation patterns. Additionally, we checked for possible climatic and edaphic factors that could affect the intraspecific covariation pattern. Key Results We found negative correlations for the LDMC–SLA, Ft–SLA, LDMC–Nm and Ft–Nm trait pairs. This intraspecific covariation pattern found both in the field and in the common garden and not explained by climatic or edaphic variation in the field follows the expected acquisitive–conservative axis. At the same time, we found quantitative differences in slopes among different species, and between these intraspecific patterns and the interspecific ones. Many of these differences seem to be idiosyncratic, but some appear consistent among species (e.g. all the intraspecific LDMC–SLA and LDMC–Nm slopes tend to be shallower than the global pattern). Conclusions Our study indicates that the acquisitive–conservative leaf functional trait covariation pattern occurs at the intraspecific level even in the absence of relevant environmental variation in the field. This suggests a high degree of variation–covariation in leaf functional traits not driven by environmental variables. 

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5. Evolutionary lineage explains trait variation among 75 coexisting grass species

   https://doi.org/10.1111/nph.18983  

   Donnelly, Ryan C.; Wedel, Emily R.; Taylor, Jeffrey H.; Nippert, Jesse B.; Helliker, Brent R.; Riley, William J.; Still, Christopher J.; Griffith, Daniel M. (August 2023, New Phytologist)

   Summary Evolutionary history plays a key role driving patterns of trait variation across plant species. For scaling and modeling purposes, grass species are typically organized into C₃vs C₄plant functional types (PFTs). Plant functional type groupings may obscure important functional differences among species. Rather, grouping grasses by evolutionary lineage may better represent grass functional diversity.We measured 11 structural and physiological traitsin situfrom 75 grass species within the North American tallgrass prairie. We tested whether traits differed significantly among photosynthetic pathways or lineages (tribe) in annual and perennial grass species.Critically, we found evidence that grass traits varied among lineages, including independent origins of C₄photosynthesis. Using a rigorous model selection approach, tribe was included in the top models for five of nine traits for perennial species. Tribes were separable in a multivariate and phylogenetically controlled analysis of traits, owing to coordination of important structural and ecophysiological characteristics.Our findings suggest grouping grass species by photosynthetic pathway overlooks variation in several functional traits, particularly for C₄species. These results indicate that further assessment of lineage‐based differences at other sites and across other grass species distributions may improve representation of C₄species in trait comparison analyses and modeling investigations. 

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