Endemic island plant-herbivore interactions: Kamehameha butterfly (Nymphalidae) and Hawaiian Urticaceae
Data files
Jan 02, 2024 version files 34.31 KB
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Bogner_etal_Bioassay_Urticaceae_Data.xlsx
26.79 KB
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README.md
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Abstract
Insect-plant interactions are less well studied than other types of herbivory on islands, precluding a comprehensive understanding of the evolutionary ecology of these interactions. Declines in native island plants and insects call for urgent attention to characterize these species’ interactions for their conservation and to better understand evolution in these unique, insular ecosystems. In Hawai‘i, the Kamehameha butterfly (Vanessa tameamea) is one of only two native butterflies, and larvae are specialists on native urticaceous plants. Using a no-choice bioassay, we investigated performance of V. tameamea reared from egg hatching through eclosion on four native urticaceous host plants, Boehmeria grandis, Pipturus albidus, Touchardia latifolia, and Touchardia oahuensis, and one exotic urticaceous species, Cecropia obtusifolia. Performance varied significantly among the plant diets, with V. tameamea performing best on P. albidus and T. oahuensis among the performance metrics of survival, pupal and adult body mass, and development time. Larval responses to the exotic host plant C. obtusifolia varied among populations, with O‘ahu caterpillars successfully completing development on it, but Hawai‘i Island caterpillars rejecting it completely, suggesting a geographic mosaic for this novel species interaction. Characterization of a suite of nutritive and defensive plant traits revealed significant variability among plant species, but patterns did not align well with V. tameamea performance rankings, making it difficult to identify key drivers of host plant quality. Future work examining additional plant traits under natural conditions would provide new insights, contributing critical ecological information to conserve this charismatic island species.
README: Endemic island plant-herbivore interactions: Kamehameha butterfly (Nymphalidae) and Hawaiian Urticaceae
https://doi.org/10.5061/dryad.866t1g1xb
Data from bioassay experiment testing performance of Kamehameha butterfly (Vanessa tameamea) on five Urticaceous host plant species. Hostplant quality data are included.
Description of the data and file structure
Bioassay_survival (Sheet 1)
Description: Survival data for Vanessa tameamea reared on five different plant diets (N=224)
butterfly_population: Vanessa tameamea population; individuals from three Hawaii populations used in the study (two from Oahu and one from Hawaii Island)
diet: the plant diet that Vanessa tameamea consumed during the bioassay
count: total number of Vanessa tameamea individuals fed a particular diet from a particular population (subgroup count)
no_total_survived_incl_deformity: total number of Vanessa tameamea individuals that survived in each diet/population subgroup from egg hatching to eclosion and includes those that eclosed with deformities that would have prevented them from taking flight in the wild
no_total_survived_excl_deformity: total number of Vanessa tameamea individuals that survived in each diet/population subgroup from egg hatching to eclosion and excludes those individuals that eclosed with deformities that would have prevented them from taking flight in the wild
Bioassay_other_metrics (Sheet 2)
Description: Growth and performance metrics for Vanessa tameamea reared on five different plant diets.
butterfly_population: Vanessa tameamea population; individuals from three Hawaii populations used in the study (two from Oahu and one from Hawaii Island)
individual_id: unique identification code for each Vanessa tameamea individual that survived through eclosion without deformities (N=157);
diet: the plant diet that each Vanessa tameamea individual consumed during the bioassay
sex: the sex of each individual Vanessa tameamea (M=male, F=female)
no_instars: the total number of instars each individual Vanessa tameamea went through before pupation
pupal_weight: the pupal mass of each individual Vanessa tameamea; the pupal mass was calculated by subtracting the ramakin lid after the butterfly eclosed (with the old chrysalis shell removed) from the ramakin lid with the attached hardened pupa (during the butterfly’s pupal stage); units: grams (g)
adult_weight: the adult mass of each individual Vanessa tameamea after it eclosed; the mass was measured eight to twelve hours after the butterfly eclosed in order to minimize variance in mass due to hemolymph loss and expulsion of the meconium; units: grams (g)
hatch_to_pupation_time: the amount of time in days it took an individual Vanessa tameamea to reach pupation (as indicated by a hardened chrysalis) starting from the day the individual hatched from an egg; units: days
hatch_to_eclosion_time: the amount of time in days it took an individual Vanessa tameamea to reach eclosion (emergence from the chrysalis as an adult butterfly) starting from the day the individual hatched from an egg; units: days
pupation_to_eclosion_time: the amount of time in days an individual Vanessa tameamea was in its pupal stage (i.e., pupation time). The start of the pupation was marked by a hardened chrysalis. Pupation time ended with the butterfly’s eclosion from the chrysalis; units: days
Plant_functional_trait _data (Sheet 3)
* Description: Functional trait data for the five plant species that *Vanessa tameamea was reared on during the bioassay. All leaves were mature and were collected from mature, wild plants from two different locations (Manoa Cliff and Pali Lookout). A total of four leaves were collected per individual plant. Two leaves were used to calculate chlorophyll, LMA, leaf thickness, carbon to nitrogen ration, phosphorus, and calcium. Two separate leaves were collected, dried, and combined for the phenolic analyses .
species: the plant species that leaves were collected from in the field for the functional trait analyses
plant_field_ID: the unique identification number for each individual plant sampled in the field
site: location of leaf collections (Pali or Manoa Cliff)
chlorophyll_spad: a unitless measurement of chlorophyll using a SPAD meter; one chlorophyll reading was taken on two different leaves per plant; chlorophyll measurements represent the average chlorophyll measurement across two leaves collected from an individual plant
LMA: a measurement (grams/meter2) of dry leaf mass divided by the area of a fresh leaf; LMA measurements represent the average LMA across two leaves collected from an individual plant
leaf_thickness: the thickness of an individual leaf in milimeters. One measurement of leaf thickness was taken on two different leaves per plant; leaf thickness measurements represent the average leaf thickness across two leaves collected from an individual plant.
CN_ratio: a unitless measurement of the ratio of carbon (milligrams/grams) to nitrogen (milligrams/grams) within a leaf. The CN ratio represents the carbon to nitrogen ratio of two leaves that were dried and then combined into one sample for carbon and nitrogen analysis.
Ca_mg_g: a measurement of the quantity of calcium (milligrams/gram) within a leaf. The leaf calcium content represent the calcium content of two leaves that were dried and then combined into one sample for the calcium testing.
P_mg_g: a measurement of the quantity of phosphorus (milligrams/gram) within a leaf. The leaf phosphorus content represent the phosphorus content of two leaves that were dried and then combined into one sample for the phosphorus testing.
Phenolic_test_ID: a unique identification number given to each leaf sample used for phenolic analyses
Total phenolics: the quantity of total phenolics (milligrams/gram) within a leaf sample; the quantity of total phenolics within each cell represents an average of three subsamples analyzed from a combined dried leaf sample from two leaves collected from an individual plant
Phenolics_post_oxidation: the quantity of remaining leaf phenolics (milligrams/gram) after a sample was oxidized; the quantity of remaining phenolics post-oxidation within each cell represents an average of three subsamples analyzed from a combined dried leaf sample from two leaves collected from an individual plant
Oxidized_phenolics: the quantity of leaf phenolics (milligrams/grams) that were oxidized within a sample; each sample contained dried leaf material from two leaves from an individual plant; the quantity of oxidized phenolics within each cell represents the subtraction average (total phenolics minus phenolics post oxidation) of three subsamples analyzed from a combined dried leaf sample from two leaves collected from an individual plant; in cases where the quantity was a negative value, the negative value was replaced with a quantity of zero
Proportion_oxidized_phenolics_to_total_phenolics: a unitless measurement of the proportion of oxidized phenolics (mg/g) divided by the number of total phenolics (mg/g) within a leaf sample; the proportion value within each cell represents the average proportion of oxidized phenolics to total phenolics of three subsamples analyzed from a combined dried leaf sample from two leaves collected from an individual plant
Code/Software
All analyses and figures were done in R 4.3.0.
Methods
Performance of Kamehameha butterflies was assessed via survival, time to eclosion, and adult biomass, in a lab bioassay experiment testing the quality of 5 plant diets. Characteristics of the five plant species used as hostplant material were assessed via chemical analyses, morphological analyses, and microscopy. Raw data are provided here.