Issues Facing Butterfly Habitat

Pollinators and Biological Control Agents

Butterflies and some moths serve two very important purposes, they provide pollination ‘services’ for flowering plants of many species as well as serving as a control agent of harmful pests.  As a pollinator of plants they are instrumental in the propagation of a wide variety of plants including fruits, vegetable and many common and exotic flowers.  Rural farmers as well as urban gardeners rely on butterflies.  “Since butterflies are regarded as generalist flower visitors the number of plant species available to them could be a function of their proboscis length” (Bauder, 2015).  Butterflies pollinate similar to bees in that the pollen sticks to their legs when collecting nectar from the plants but they are different and utilize their specific collect or proboscis from specific plant species.  “These easily accessible flowers are continuously exploited by a great variety of butterfly species possessing rather short proboscis, whereas the long-proboscid skippers are crowded out to deep-tubed flowers, where they can benefit from a more exclusive access to nectar” (Bauder, 2015). So, even though bees are more well-known as pollinators the Lepidoptera have a specific function and serve a specific and useful pollinating purpose.

As a control agent butterflies and their larval a pupae stages are very important as a biological control agent and are used in many regions globally as a natural control to invasive species that harm endemic plants. “Several species of Lepidoptera have been extensively used in the biological control of invasive plants” (Morais, 2011).  Using Lepidoptera is not the only type of insect to serve this purpose, but they are a very important contributor because of their ability to survive and spread into other regions.  “Establishment and spread are two distinct issues in biological control programs of weeds” (Morais, 2011).  Because Lepidoptera have these two characteristics they make excellent productive and economical use as a biological alternative to chemical pesticide.  It is especially the speed in dispersal that may make all the difference between success and failure as a management tool.  “Among the main arthropod groups used in biological control programs of weeds (Acarina, Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and Thysanoptera), Lepidoptera were the fastest dispersers” (Morais, 2011).

Threats to habitat – natural and human

While moths and butterflies appear to survive in both rural and urban ecosystems they are still threatened in both areas.  Like many of the areas other animal and plant species suffer throughout the world today butterflies suffer the same fate – habitat fragmentation.  Of course, there are pockets of habitats that support butterfly propagation.  But even these pockets can be easily threatened.  “For example, agricultural cultivation, mowing, weeding, trampling and grazing during egg and larval stages.  The host plant is destroyed and then larvae are killed, especially in the second and third generation when farmers’ agricultural activities are more intense” (Li, 2016).  It is important to protect these habitat areas in all stages of the butterflies’ life-cycle.  The upside of this is that many of the habitats that the butterfly and moths prefer is marginal territory left unused by farmers in agriculture or human development.  “Their preferred habitat occurs along field margins, paths and irrigation ditches” (Li, 2016).  In fact, these are edge habitat’s that provide shelter and open areas in which to collect pollen.  The important issue is that these areas are left undisturbed for the most part.  , “A key factor of the first and second generation are natural enemies, which cause mortality up to 86% for eggs and 64% for larvae.  But in the third generation human activities have been identified as the key factor, which causes mortality of up to 42% for eggs and 75% for larvae” (Li, 2016). 

Conclusion

Like many issues facing all ecosystems world-wide butterfly habitat is also threatened.  Human initiated development is a contributing factor as is intensive and extensive farming as well as the ubiquitous use of herbicides and pesticides.  Additionally, simply mowing a vacant field populated by clover and other cover crops can be butterfly and moth habitat.  This in fact happened recently which was a neighborhood ‘hotspot’ for butterfly sightings that I used during my Citizen Science project.  Understanding our actions as a community before using historical methods to shrink habitat for butterflies, moths and other Anthropods would make a huge difference with minimal effect to human productivity.

References:

Bauder, J., Warren, A., Krenn, H., “The ecological role of extremely long-proboscid Neotropical butterflies (Lepidoptera: Hesperiidae) in plant-pollinator networks”, Anthropod – Plant Interactions, June 2, 2015

Li, X., Luo, Y., et. al., “On the Ecology and Conservation of Sericinus montelus (Lepidoptera: Papilionidae) – Its threats in Xiaolongshan Forests Area (China), PLOS ONE, March 22, 2016.

Morais, E., Picanco, M., et.al., “Lepidopterans as potential agents for the biological control of the invasive plant, Miconia calvescens”, Journal of Insect Science, October 24, 2011.

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