scholarly journals Distribution and phenology of monarch butterfly larvae and their milkweed hosts in the South Central US

2022 ◽  
Author(s):  
James L Tracy ◽  
Tuula Kantola ◽  
Kristen A. Baum ◽  
Robert N. Coulson
Keyword(s):  
Land Cover ◽  
Spatial Density ◽  
Conservation Priorities ◽  
The South ◽  
Conservation Assessment ◽  
Early Season ◽  
Late Season ◽  
South Central ◽  
Larval Host ◽  
Host Selectivity

Abstract South Central US milkweeds (Asclepias) are critical adult nectar and larval food resources for producing the first spring and last summer/fall generations of declining eastern migratory monarch butterflies (Danaus plexippus). This study addresses multiple gaps in assessment of monarch conservation priorities for the South Central US through analyses of monarch larval host selectivity, phenology, and spatial density, as well as the phenology, niche modeled distribution, and land cover selectivity of important milkweed hosts. Results are synthesized to estimate seasonal milkweed resource areas. About 70% of monarch larval activity occurred from mid-March to mid-July (early season) and 30% from mid-August to late November (late season). Twenty-six wild milkweed (Apocynaceae) hosts were mapped, including four new records for North America. Important hosts included Asclepias a. ssp. capricornu, A. viridis, and A. oenotheroides, that were utilized more frequently during early season, and Asclepias latifolia, utilized more frequently during late season. Landscape host selectivity was positive for A. viridis and A. a. ssp. capricornu in late and early seasons, respectively, and negative for A. oenotheroides in late season. Milkweed land cover selectivity was positive for Developed-Open Space and Grassland Herbaceous, and negative for Cultivated Crops and Shrub/Scrub. Seasonal milkweed resource areas and larval spatial densities resolved interior and coastal corridors providing functional connectivity for monarch spring and fall migrations. A potential gap in milkweed land cover benefit was identified in South Texas. The novel merging of milkweed niche models with larval phenology, host selectivity, milkweed phenology, and land cover selectivity informs conservation assessment.

scholarly journals Distribution, phenology, and land cover preference risk assessments of four South-Central US milkweeds (Asclepias spp.) important for monarch butterflies

2021 ◽  
Author(s):  
James L Tracy ◽  
Tuula Kantola ◽  
Kristen A Baum ◽  
Robert N Coulson
Keyword(s):  
Land Cover ◽  
Open Space ◽  
Danaus Plexippus ◽  
Bias Reduction ◽  
Risk Assessments ◽  
Larval Food ◽  
Science Data ◽  
Monarch Butterflies ◽  
Late Season ◽  
South Central

Abstract South-Central US milkweeds (Asclepias spp.) are critical adult nectar and larval food resources for producing the first spring and last summer/fall generations of declining eastern migratory monarch butterflies (Danaus plexippus). MaxEnt niche models were developed for North American ranges of four important South-Central US milkweeds: Asclepias asperula ssp. capricornu, A. viridis, A. oenotheroides, and A. latifolia. Twelve models per species utilized subsets of six to eight of 95 edapho-topo-climatic variables chosen by a random subset feature selection algorithm. Milkweed weekly phenology was compared between early and late season periods of monarch activity. Novel land cover preference risk assessments were developed for milkweeds through land cover utilization-availability analyses, incorporating a novel sample bias reduction method for citizen science data before calculation of relativized electivity index (E*) land cover preference. Asclepias a. ssp. capricornu and A. viridis occurred more frequently during early season monarch activity, while A. oenotheroides and A. latifolia occurred more frequently during late season monarch activity. Milkweed utilization of roadsides varied from 6–31%. Developed-Open Space and Grassland Herbaceous land classes generally had highest benefit among milkweeds. Cultivated Crops and Shrub/Scrub had high risk. Combined milkweed high Ei* kernel density estimation surfaces resolved interior and coastal corridors of milkweed land cover preference providing functional connectivity for the monarch spring and fall migrations. A potentially critical gap in milkweed land cover benefit connectivity was identified in South Texas. Milkweed land cover preference risk assessments can be used to prioritize milkweed habitat conservation for enhancing monarch migration connectivity across the South-Central US.

scholarly journals Orchidantha anthracina (Lowiaceae), a new species from Vietnam

2020 ◽  
Vol 65 (1) ◽  
pp. 90-93
Author(s):  
H.Đ. Trân ◽  
H.T. Lu'u ◽  
J. Leong-Škorničková
Keyword(s):  
New Species ◽  
The South ◽  
Conservation Assessment ◽  
Central Coast ◽  
Number Of Species ◽  
South Central ◽  
The Family ◽  
Coast Of Vietnam ◽  
A New Species

Orchidantha anthracina (Lowiaceae), discovered at the south central coast of Vietnam, is described and illustrated, bringing the total number of species in the family to 26, of which four occur in Vietnam. The notes on distribution, habitat and etymology are given and a preliminary conservation assessment is provided. The species is compared with O. vietnamica, with which it shares flowers of similar size and colours, but from which it is readily distinguished by a narrow and strongly reflexed dorsal sepal and spreading lateral sepals, not supporting the labellum. Notes with additional comparison to all species with a similar arrangement of lateral sepals are also provided.

scholarly journals Using Fluridone Herbicide Systems for Weed Control in Texas Cotton (Gossypium Hirsutum L.)

2020 ◽  
Vol 11 ◽  
pp. 1-14
Author(s):  
James Grichar ◽  
Peter A. Dotray ◽  
Joshua McGinty
Keyword(s):  
Weed Control ◽  
Cucumis Melo ◽  
High Plains ◽  
Amaranthus Palmeri ◽  
Weed Species ◽  
Early Season ◽  
Late Season ◽  
South Central ◽  
One Year ◽  
The One

Studies were conducted during 2015 through 2018 in south-central, Coastal Bend, and Southern High Plains areas of Texas to evaluate fluridone herbicide systems for weed control and cotton response. Fluridone alone at 0.17 to 0.23 kg ai ha-1 followed by postemergence (POST) herbicides controlled Amaranthus Palmeri 82 to 100% season-long while Cucumis melo control ranged from 92 to 100%. Control of Urochloa Texana with fluridone alone ranged from 40 to 96% early-season while late-season control ranged from 37 to 96%. Fluridone plus fomesafen systems controlled A. Palmeri, C. Melo, and U. Texana at least 98% early season; however, late-season control of A. Palmeri was less than 70% while C. Melo control was 91% and U. Texana control was 80%. Adding a POST application of glyphosate to fluridone plus fomesafen improved control to at least 98% for all three weed species. Fluridone plus fluometuron combinations provided similar control to fluridone plus fomesafen. Adding glyphosate (POST) improved A. Palmeri control to at least 82% season-long. Cotton yields reflect the level of weed control with significantly better yields from fluridone systems compared with the weedy check. However, in the one year when the untreated was maintained weed-free, no differences in cotton yield were noted between the weed-free and any herbicide treatment.

Sign in / Sign up

Export Citation Format

Share Document