Module 12

Question 1

Benefits of arthropods to human and animal health

Answer 1

Decomposers → turn dead plants and animals into soil nutrients
Production of honey and beeswax
Production of silk
Production of materials used in medicine
Source of food

Question 2

Arthropods as sources of food

Answer 2

Crickets are the main source of insect used in food production
- Contain 69% of protein
- High amounts of vitamin B12
- High calcium and iron quantities

Overall reduction in greenhouse gas emissions with insects used as a source of food
- Decreased agricultural land use
Management of chronic diseases
Overall less negative impacts on the environment and resources

Insects are also considered for animal feed
- Brings down costs of protein for feed production → larvae of black soldier flies
- Products produced by insects also have nutritional and health value
- Pollination and agricultural benefits
- Health benefits → immunity, regulation of blood sugar, source of probiotic

Question 3

Hazards of arthropods

Answer 3

Hematophagy: feeding on blood
A behaviour that has evolved in certain groups of arthropods to utilise animals as a food source
- Accompanied by specific adaptations of their mouthparts for biting and sucking
- Some of the hematophagous arthropods may also obtain other sources of food → mosquitoes get sugars from feeding on plant nectars, but blood is still needed as a source of protein for egg production
Blood feeding is a major physiological event in the life cycle of certain groups of arthropods

Question 4

Mosquitos

Answer 4

Mosquitoes take a large amount of blood equal or more than its weight
This leads to the enlargement of its abdomen
While they take a blood meal, arthropods inject a bit of their saliva into the host
This saliva contains components that inhibit blood clotting and dilation of blood vessels, helping the process of blood feeding
There are also histamines in the saliva that cause itching, discomfort, and pustule formation on the skin
If the host is infected with a pathogen that is present in the blood, including viruses or unicellular parasites, the arthropod can transmit the pathogen to other hosts on its subsequent blood feeding events
Most of these pathogens need to replicate and develop inside the arthropod before they are transmitted
The pathogen eventually infects the salivary glands of the hematophagous arthropod and is easily transmitted during blood feeding

Question 5

Arthropods as a source of allergy

Answer 5

Body parts, saliva, or faeces from some arthropods could be sources of allergy
Dust mites – the feces and decaying bodies contain allergic components causing asthma

Question 6

Arthropods as a source of venom

Answer 6

Many species of arthropods produce venom to subdue their prey or for defence
- When they encounter humans or animals, they deliver their venom that could cause mild to severe issues, or even death
Some venom is used for relieving chronic pain or treating cancer