scholarly journals High Survivorship of First-generation Monarch Butterfly Eggs and Larvae Associated with a Diverse Arthropod Community

Author(s):  
Misty Stevenson ◽  
Kalynn L. Hudman ◽  
Alyx Scott ◽  
Kelsey Contreras ◽  
Jeffrey G. Kopachena

The eastern migratory population of the monarch butterfly (Danaus plexippus) in North America has declined by over 80% in the last 20 years, prompting the implementation of numerous conservation strategies. However, there is little information on the survivorship of first-generation monarchs in the core area of occupancy in Texas, Oklahoma, and Louisiana where overwinter population recovery begins. The purpose of this study was to determine the survivorship of first-generation eggs to third instars at a site in north Texas and to evaluate host plant arthropods for their effect on survivorship. Survivorship to third instar averaged 13.4% and varied from 11.7% to 15.6% over three years. The host plants harbored 77 arthropod taxa, including 27 predatory taxa. Despite their abundance, neither predator abundance nor predator richness predicted monarch survival. However, host plants upon which monarchs survived often harbored higher numbers of non-predatory arthropod taxa and more individuals of non-predatory taxa. These results indicate that indirect top-down effects improved monarch survival in our study. The creation of diverse functional arthropod communities should be considered for effective monarch conservation, particularly in southern latitudes.

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 567
Author(s):  
Misty Stevenson ◽  
Kalynn L. Hudman ◽  
Alyx Scott ◽  
Kelsey Contreras ◽  
Jeffrey G. Kopachena

Based on surveys of winter roost sites, the eastern migratory population of the monarch butterfly (Danaus plexippus) in North America appears to have declined in the last 20 years and this has prompted the implementation of numerous conservation strategies. However, there is little information on the survivorship of first-generation monarchs in the core area of occupancy in Texas, Oklahoma, and Louisiana where overwinter population recovery begins. The purpose of this study was to determine the survivorship of first-generation eggs to third instars at a site in north Texas and to evaluate host plant arthropods for their effect on survivorship. Survivorship to third instar averaged 13.4% and varied from 11.7% to 15.6% over three years. The host plants harbored 77 arthropod taxa, including 27 predatory taxa. Despite their abundance, neither predator abundance nor predator richness predicted monarch survival. However, host plants upon which monarchs survived often harbored higher numbers of non-predatory arthropod taxa and more individuals of non-predatory taxa. These results suggest that ecological processes may have buffered the effects of predators and improved monarch survival in our study. The creation of diverse functional arthropod communities should be considered for effective monarch conservation, particularly in southern latitudes.


1984 ◽  
Vol 32 (5) ◽  
pp. 663 ◽  
Author(s):  
DG James

Data were obtained on population and general biology of three non-reproductive overwintering colonies ofthe monarch butterfly, Danaus plexippus (Danaidae) during April-August in 1980,1981 and 1982 at a site near Camden in New South Wales. A mark, release and recapture study showed that the 1981 colony was largely stable and the 1982 colony was migratory. In 1980 and 1981 populations comprised less than 500 individuals but in 1982 a peak population of 3500 butterflies was recorded. Males were sexually active throughout clustering. Most females were mated but showed no ovarian development. Periods of flight and feeding activity were common. The condition of most butterflies did not deteriorate markedly during clustering. Comparisons between winter non-reproductive monarch populations in North America and Australia are discussed.


Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 384
Author(s):  
Ramiro Pérez-Miranda ◽  
Víctor Javier Arriola-Padilla ◽  
Martín Enrique Romero-Sanchez

Every year, Danaus plexippus (Linnaeus, 1758) travels to hibernate in oyamel fir forests located between the limits of the states of Michoacán and Mexico in Mexico. Climate change and anthropogenic actions are diminishing oyamel fir forests in Mexico, putting pressure on the habitats of monarch butterflies. In the last decade, new colonies outside their usual range have been predicted through modeling and reported by the National Commission on Protected Areas of Mexico. The objectives of the study were to recover information on the historical and new hibernation sites, reported or modeled, from different literature sources. We also aimed to perform a bioclimatic and forest biometric characterization of new monarch butterfly colonies located in Sierra Nevada in Mexico to provide information to aid in conservation strategies for the monarch butterfly population. We conducted field trips to georeference the colonies at sites located in the Atlautla municipality in Mexico State. Climatic, topographic, and forest biometric variables were used to characterize the sites physically. It was found that the butterfly’s roosts occurred at a higher elevation than those recorded by other sources. The locations where the monarch’s colonies were established, in the east of Mexico State, provide information relevant to defining and developing policies for their conservation.


2019 ◽  
Vol 116 (8) ◽  
pp. 3006-3011 ◽  
Author(s):  
J. H. Boyle ◽  
H. J. Dalgleish ◽  
J. R. Puzey

Monarch butterfly (Danaus plexippus) decline over the past 25 years has received considerable public and scientific attention, in large part because its decline, and that of its milkweed (Asclepias spp.) host plant, have been linked to genetically modified (GM) crops and associated herbicide use. Here, we use museum and herbaria specimens to extend our knowledge of the dynamics of both monarchs and milkweeds in the United States to more than a century, from 1900 to 2016. We show that both monarchs and milkweeds increased during the early 20th century and that recent declines are actually part of a much longer-term decline in both monarchs and milkweed beginning around 1950. Herbicide-resistant crops, therefore, are clearly not the only culprit and, likely, not even the primary culprit: Not only did monarch and milkweed declines begin decades before GM crops were introduced, but other variables, particularly a decline in the number of farms, predict common milkweed trends more strongly over the period studied here.


1988 ◽  
Vol 120 (5) ◽  
pp. 415-424 ◽  
Author(s):  
R. E. Pfadt ◽  
J. A. Lockwood ◽  
T. M. Foppe

AbstractExamination of crop contents of three species of grasshoppers in outbreak densities on desert grassland of eastern Arizona revealed that all three were ingesting a mixed diet of plants. Crops of nymphal and adult Aulocara elliotti (Thomas) contained an average of 67 and 93% dry weight of grass, respectively, placing this species in both the mixed graminivorous and the graminivorous categories. The preferred host plant of A. elliotti was Bouteloua gracilis (H.B.K.) Lag. but it was not an essential item, as a large population developed in a site where this grass was virtually lacking but other perennial grasses were present. Crops of nymphs and adults of both Melanoplus sanguinipes (Fabricius) and M. cuneatus Scudder contained chiefly forbs (88–100% of dry weight). The principal host plants were Erodium cicutarium (L.) L’Hér., Lupinus brevicaulis Wats., Microsteris gracilis (Hook.) Greene, and Plantago purshii Roem. & Schult. Both species of Melanoplus fit into the forbivorous category and evidence indicated they were in competition with each other for food. All three grasshopper species showed preferences for particular plant species and as a consequence had significantly different frequencies of plant taxa in their crop contents from what were present in the field.


2017 ◽  
Vol 46 (3) ◽  
pp. 626-632 ◽  
Author(s):  
Jamie L. Rafter ◽  
Justin F. Vendettuoli ◽  
Liahna Gonda-King ◽  
Daniel Niesen ◽  
Navindra P. Seeram ◽  
...  

Abstract Prey have evolved a number of defenses against predation, and predators have developed means of countering these protective measures. Although caterpillars of the monarch butterfly,Danaus plexippus L., are defended by cardenolides sequestered from their host plants, the Chinese mantidTenodera sinensis Saussure guts the caterpillar before consuming the rest of the body. We hypothesized that this gutting behavior might be driven by the heterogeneous quality of prey tissue with respect to toxicity and/or nutrients. We conducted behavioral trials in which mantids were offered cardenolide-containing and cardenolide-freeD. plexippus caterpillars and butterflies. In addition, we fed mantids starved and unstarvedD. plexippus caterpillars from each cardenolide treatment and nontoxicOstrinia nubilalis Hübner caterpillars. These trials were coupled with elemental analysis of the gut and body tissues of bothD. plexippus caterpillars and corn borers. Cardenolides did not affect mantid behavior: mantids gutted both cardenolide-containing and cardenolide-free caterpillars. In contrast, mantids consumed bothO. nubilalis and starvedD. plexippus caterpillars entirely.Danaus plexippus body tissue has a lower C:N ratio than their gut contents, whileO. nubilalis have similar ratios; gutting may reflect the mantid’s ability to regulate nutrient uptake. Our results suggest that post-capture prey processing by mantids is likely driven by a sophisticated assessment of resource quality.


2021 ◽  
Vol 118 (16) ◽  
pp. e2024463118
Author(s):  
Anurag A. Agrawal ◽  
Katalin Böröczky ◽  
Meena Haribal ◽  
Amy P. Hastings ◽  
Ronald A. White ◽  
...  

For highly specialized insect herbivores, plant chemical defenses are often co-opted as cues for oviposition and sequestration. In such interactions, can plants evolve novel defenses, pushing herbivores to trade off benefits of specialization with costs of coping with toxins? We tested how variation in milkweed toxins (cardenolides) impacted monarch butterfly (Danaus plexippus) growth, sequestration, and oviposition when consuming tropical milkweed (Asclepias curassavica), one of two critical host plants worldwide. The most abundant leaf toxin, highly apolar and thiazolidine ring–containing voruscharin, accounted for 40% of leaf cardenolides, negatively predicted caterpillar growth, and was not sequestered. Using whole plants and purified voruscharin, we show that monarch caterpillars convert voruscharin to calotropin and calactin in vivo, imposing a burden on growth. As shown by in vitro experiments, this conversion is facilitated by temperature and alkaline pH. We next employed toxin-target site experiments with isolated cardenolides and the monarch’s neural Na+/K+-ATPase, revealing that voruscharin is highly inhibitory compared with several standards and sequestered cardenolides. The monarch’s typical >50-fold enhanced resistance to cardenolides compared with sensitive animals was absent for voruscharin, suggesting highly specific plant defense. Finally, oviposition was greatest on intermediate cardenolide plants, supporting the notion of a trade-off between benefits and costs of sequestration for this highly specialized herbivore. There is apparently ample opportunity for continued coevolution between monarchs and milkweeds, although the diffuse nature of the interaction, due to migration and interaction with multiple milkweeds, may limit the ability of monarchs to counteradapt.


Author(s):  
Norman Herz ◽  
Ervan G. Garrison

This chapter is only a brief introduction to lithic archaeological materials. Archaeologists with but little knowledge of rocks and rock-forming minerals are urged to learn about them in greater detail than that presented here. Lithic resources are abundant in almost every archaeological site, and lithic artifacts are invariably the best preserved of any remains. Early societies learned how to exploit these resources, and the use and production of lithics go back to the earliest known sites, at least 1.5 million years. In fact, the earliest cultures are distinguished on the basis of their lithic industries and lithic artifacts. Horror stories in misidentification of lithics abound. Not only have misidentified artifacts proven embarrassing to the archaeologist, but also they have made it difficult to make meaningful comparisons of different societies using published descriptions. In addition, conservation strategies for historical monuments cannot be developed without an understanding of the nature of the material used in their construction. Some egregious examples of ignorance of the rocks and minerals from our personal experience include the following: 1. An archaeologist asked if a quartzite scraper was either flint or chert. When told that it was neither, he asked, "Well then, which is it more like?" (answer, still neither). 2. Egyptian basalt statues have been called limestone in publications (and several other rock types). 3. Sources for alabaster were searched to explain a trading link between a site and elsewhere when the geological map showed the site was adjacent to a mountain of gypsum, the mineral component of alabaster (the gypsum may have merely rolled down the hillside to the workshops, where it became the more salable alabaster). 4. Conservators searched for methods to preserve an allegedly granitic historic monument, or so it had been identified. Chemical analysis revealed only abundant Ca, Mg, and carbonate. Fossils were also abundant in the "granite," which dissolved easily in hydrochloric acid (the "granite" was clearly limestone). Petrology is the branch of geology that deals with the occurrence, origin, and history of rocks. Petrography is concerned with descriptions of rocks, their mineralogy, structures, and textures.


2020 ◽  
Vol 11 (4) ◽  
pp. 42-63
Author(s):  
Karen Kesler ◽  
Rick Bunch

The purpose of this research was to relate the influence of specific site suitability variables to eastern monarch butterfly migratory patterns and behavior. Elevation, temperature, precipitation, and land use data layers were overlaid to collectively consider how these variables affected the way that butterflies migrated and recolonized during the 2016/2017 migratory cycle. The variables were reclassified into layers ranking suitability as either unsuitable, suitable, or optimal with respective scores of one, three, and five. Three uninhabitable variables were identified that deemed a site unsuitable despite the influence and possible optimal suitability of the other variables. The results of this study indicated that site suitability was a large driving factor for migratory monarchs with a heavier emphasis placed on average temperature and land/cropland use. Possible displaced and sink populations were identified for further study, while the effects of agriculture, development, and climate change were considered regarding flyway connectivity and behavior.


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