Insect Communication and Special Topics in Entomology

Special Topics in Entomology

• Insect Migration
  • Monarch Butterflies
  • Embark on a spectacular migration journey, covering over 3,000 miles from Southern Canada to Central Mexico.
  • They are classified as milkweed butterflies, primarily feeding on milkweed as larvae and nectar as adults.
  • Multiple population groups exist, including Eastern, Midwestern, and Western populations.
  • About 2 billion monarchs migrate to specific regions in Mexico, often requiring up to four generations to complete their annual migration cycle.
  • Southern Migration:
    • Begins around October, as the butterflies travel south for wintering.
    • Super generation monarchs live longer (up to eight times longer than those migrating north) and seek higher elevation areas for stable winter conditions.
    • They do not eat during the winter; they rely on stored energy.
    • Necessary conditions include access to trees such as Eucalyptus and Monterey pines for roosting and a reliable water source.
  • Northern Migration:
    • Starts in early spring (March) when the overwintering generation begins its journey north.
    • As they migrate, they lay eggs on milkweed plants, which caterpillars feed on, leveraging the toxic properties of the plants for defense.
    • Requires two to three generations to return to their original northern habitats.
    • During this cycle, they enter a reproductive diapause, investing energy in lipid storage for migration rather than reproduction.

Invasive Insect Species

• Definition of Invasive Species:
  • Non-native species that outcompete existing endemic species, leading to ecological harm and economic impact.
  • Invasive species can be introduced intentionally (e.g., cane toads in Australia) or accidentally (e.g., black rats on ships).
  • Not every non-native species is invasive; the distinction lies in their ecological impact.
  • In the U.S., over 6,500 invasive species have been identified, leading to significant economic losses (e.g., $26 billion in 2010).

Examples of Invasive Insect Species:

1. Emerald Ash Borer:

   • Originated in Asia, first detected in Michigan in 2002.
   • Feeds on ash trees, disrupting vascular systems and causing tree death. Management strategies include quarantining, tree removal, insecticides, and biological controls involving parasitoid wasps.

2. Spotted Lanternfly:

   • From Asia, discovered in the U.S. in the 1990s.
   • Targets over 70 plant species, sucking sap and producing honeydew, causing mold and damage to crops.
   • Management includes public awareness for finding egg masses, pesticide applications, and sticky traps (with wildlife safety concerns).

3. Brown Marmorated Stink Bug:

   • Discovered in the U.S. in Pennsylvania.
   • Feeds on diverse crops, leading to severe economic loss (e.g., $37 million in 2010) and impacting fruit health.
   • Management strategies include using artificial pheromones for trapping and perimeter insecticides.

4. Africanized Bees:

   • Hybridization of honeybee species that began in Brazil in the 1950s.
   • These bees are more aggressive and can crowd out European honeybee populations.
   • Control measures include managing queen populations and using colder climates to eliminate hybrid hives.

Schmidt Sting Pain Index

• Developed by entomologist Justin Schmidt, ranks stings based on pain intensity.
• Pain level includes descriptions and the consequences of being stung by insects like bullet ants and tarantula hawks.

Cordyceps Fungus

• Cordyceps fungi infect insects, taking over behavior and physiology, controlling hosts to maximize spore dispersal.
• Highly host-specific, they alter the insect's behavior, programming them to ascend to optimal microenvironments for fungal growth before killing them.
• Impact on insect populations helps regulate numbers within tropical ecosystems.

Disease Vectors

• Insects as vectors for diseases include mosquitoes (transmitting malaria, dengue), ticks, and fleas (responsible for plague).
• Malaria Lifecycle:
  • Involves both humans and mosquitoes, cycling between sporozites entering the human bloodstream and then liver, followed by red blood cell infection and back to mosquitoes for reproduction.
  • Severe impact includes high mortality rates due to anemia and systemic failure in infected individuals.