NATS 1940 Lecture Notes - Lecture 1: Monarch Butterfly, HerbicideExam
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Puneet Shergill- 214909691
SC/NATS 1940 – Assignment #3
Dr. Mark Vicari
February 8, 2018
Observed monarch butterfly behaviour has significant implications for species survival
Habitat loss is one of the worlds leading causes of species decline and extinction. New research
was completed that thus showed that egg-laying monarchs much prefer off-road farmlands
present with milkweed than along roadsides.
In the past 20 years, the eastern North American monarch butterfly population has jumped by
95%, making them much closer to extermination. A method of aiding in saving the butterflies,
was to plant more milkweeds. Reason being, every spring in North America, monarch
butterflies scheme north of their wintering grounds, laying their eggs specifically on milkweeds,
which are the only solitary plants their caterpillars can consume. Roadside parks have been
involved through this strategy. Adding on, new research unfolds that eastern North American
monarch butterflies lay three and a half times more eggs on milkweeds that are situated on
farmlands, compared to milkweeds that grow alongside roadsides, natural areas or urban
This research also expresses that monarch butterflies would rather lay their eggs in small
milkweed patches rather than large milkweed patches.
Monarch populations in eastern and western North America have experienced major decline
from the past two decades. Staying in their Mexico grounds and the appearance in southern
California a reason for habitat loss. By their traveling pathways, monarch caterpillars surface
shortages in food because of the demolition of milkweed plants in farmlands that practice
herbicide resilient crops, adding on, monarch butterflies lose their life from pesticides. Another
worry regards about the consequence of change in weather on the cycle of breeding and
survival in winter.
Efficient habitat refurbishment necessitates an understanding and acknowledgement of species
habitat choices and the related tools guiding those choices. Research studied the cycles and
causes of oviposition likings for the monarch butterfly in both areas, landscape and milkweeds.
Favorites in oviposition was influenced by size and density of milkweed.
Milkweed patches that were found on agricultural landscapes tended to have the highest egg
density than all other types of milkweed patches in any other area including roadside
landscapes. Milkweeds that were found to be medium-sized were found to have had the
highest predator profusion. Differences in the profusion of parasitoids, and the existence of
parasites of monarch eggs and larvae did not show to agree with chosen area for egg laying.
The results proposed that devoting much more time on milkweed refurbishment along roadside
habitats must be completed carefully. A better idea was suggested stating for managers to
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