environmental health course

1. Arba Minch University
College of Medicine and Other Health
Department of Environmental Health
Medical entomology and vector control
submitted to:-Lakew D.(MPH)
Date:-28/12/2014
submitted by:- Loza Yimegn
ID:- NSR/006/13

2. Content
Arthropods
Introduction
Advantage of Arthropods
Disadvantage of Arthropods
Common malaria vector spp
Anopheles Albritarsis
Anopheles Minimus
Anopheles pharonesis
Anopheles sergentii
Insect Behavior and Activity
Insect Behavior
Insect activity

3. Arthropods
Introduction
Arthropods are invertebrate animals with bilateral symmetry, segmented
bodies, jointed appendages, and a hard outer covering, called an exoskeleton.
Arthropods a segmented body, and paired jointed appendages. Arthropods
form the phylum Arthropoda. They are distinguished by their jointed limbs
and cuticle made of chitin, often mineralized with calcium carbonate. The
arthropod body plan consists of segments, each with a pair of appendages.
Arthropods are bilaterally symmetrical and their body possesses an external
skeleton. In order to keep growing, they must go through stages of mounting, a
process by which they shed their exoskeleton to reveal a new one. Some
species have wings. They are an extremely diverse group, with up to 10 million
species., more than any other animal group. For instant, ants and bees,
arachnids, such as spiders and scorpions, centipedes and millipedes, and
crustaceans, such as lobsters and crabs, are all types of arthropods. However,
Arthropods also found nearly everywhere on earth, from rainforests to deserts,
the ocean, and even in homes.

4. Advantage of Arthropods
Importance of Arthropods in Ecological Roles
Many arthropods have extremely important roles in ecosystems. Arthropods are of ecological importance
because of their sheer numbers and extreme diversity. As mentioned above, bees, wasps, ants, butterflies,
moths, flies and beetles are invaluable agents of pollination. Pollens and grains became accidentally attached
to their chests and legs and are transferred to other agricultural crops as these animals move about, either by
walking or flying. Most plants actually produce scents to send signals to insects that food (in the form of
nectar) is available. Mites, ticks, centipedes, and millipedes are decomposers, meaning they break down dead
plants and animals and turn them into soil nutrients. This is an important role because it supplies the plants
with the minerals and nutrients necessary for life. It also keeps dead material from accumulating in the
environment. Plants then pass along those minerals and nutrients to the animals that eat the plants.
Importance's of Arthropods in Pest Control
Humans use mites to prey on unwanted arthropods on farms or in homes. Other arthropods are used to
control weed growth. Populations of whip scorpions added to an environment can limit the populations
of cockroaches and crickets. Millipedes also control the harmful growth of destructive fungi and bacteria.
When the numbers of millipedes is low, the imbalance between predator and prey can cause harmful
microorganisms to flourish, and it can became difficult to manage plagues and diseases through natural
processes. Cockroaches, spiders, mites, ticks and all other insects considered as carnivorous, prey on
smaller species to maintain ecological balance. Thus, communities that have a good balance of these
arthropods tend to have better pest control.

5. Importance of Arthropods in Human uses
Arthropods are also invaluable to humans, as they are used in many different humanmade products. Examples are:
• Bees produce honey and their honeycombs contain beeswax, widely used for making candles, furniture wax and polishes,
waxed papers, antiseptics, and fillings for surgical uses.
• The pollens stored in honeycombs were discovered to have a rich mixture of vitamins ,enzymes , and amino acids that could
provide medical benefits. They were used as ingredients for supplements and medications that could provide relief for colds,
asthma, and hay fever.
• Silk produced by arthropods, like those produced by caterpillars to protect their cocoons, is strong enough to use and be woven
into fabrics, a discovery first used in ancient China's silk industry.
• The spiders’ web was discovered as an additional material that could provide strength, and has became essential raw materials
for Kevlar vests, fishing nets, surgical sutures, and adhesives, as they contained natural antiseptics.
Importance of Arthropods in Foods
Many species of crustaceans, especially crabs, lobsters, shrimp, prawns, and crayfish, are consumed by humans, and are now farmed
on a large commercial scale. Nearly 10,000,000 tons of arthropods as food were produced in 2005. Over 70% by weight of all
crustaceans caught for consumption are shrimp and prawns. Over 80% is produced in Asia, with China producing nearly half the
world’s total. In fact, there are more than 1,900 edible insect species on Earth, hundreds of which are already part of the diet of
about two billion people worldwide. This is just under one of every three people worldwide, and this number should continue to
grow in the future

6. Disadvantage of Arthropods
- Exoskeletons must be shed when an animal grows, leaving them without protection.
- Exoskeletons limit size and mobility.

7. Common malaria vector spp
• Anopheles Albritarsis
Mosquitoes belonging to the Albritarsis Group (Anopheles:
Nyssorhynchus) are of importance as malaria vectors across the
Neotropics. The Group currently comprises six known species, and
recent studies have indicated further hidden biodiversity within the
Group. DNA barcoding has been proposed as a highly useful tool for
species recognition, although its discriminatory utility has not been
verified in closely related taxa across a wide geographic distribution.
Life cycle
Life stages is Like all mosquitoes, anophelines go through four stages
in their life cycles: egg, larva, pupa, and imago. The first three
stages are aquatic and together last 5–14 days, depending on the
species and the ambient temperature. The adult stage is when the
female Anophebehaviles mosquito acts as malaria vector.
Behavior
Attacks Humans and Domestic animals indoors and outdoors.it
resting place is usually outdoors.

8. • Anopheles Minimus
Anopheles minimus is considered an important malaria vector
throughout forested regions of the SEAR particularly outside of
India (namely, China, Thailand, Myanmar, Cambodia, Vietnam, and
Laos . There are three species within this complex, with two capable
of malaria transmission. Again, this species complex exhibits high
levels of plasticity in both ecological and behavioral traits across the
region
Life cycle
Life stages is Like all mosquitoes, anophelines go through four stages
in their life cycles: egg, larva, pupa, and imago. The first three
stages are aquatic and together last 5–14 days, depending on the
species and the ambient temperature. The adult stage is when the
female Anophebehaviles mosquito acts as malaria vector.
Behavior
Occurs Habitat is shaded areas around flowing waters, irrigation
ditches and rice fields. Feeding is primarily on humans but
occasionally domestic animals. Adults rest mostly indoors.

9. • Anopheles pharonesis
Anopheles pharoensis, the type species of the
subgenus Cellia, is a grayish mosquito with a pale-scaled
abdomen sporting dark, laterally-projecting scale tufts. It is
informally placed within the Cellia Series together with An.
Also Anopheles pharoensis Theobald was found to be the
prevalent man-biting anopheline mosquito in the central
area of the Senegal River delta.
• Life cycle
Life stages is Like all mosquitoes, anophelines go through four stages
in their life cycles: egg, larva, pupa, and imago. The first three
stages are aquatic and together last 5–14 days, depending on the
species and the ambient temperature. The adult stage is when the
female Anophebehaviles mosquito acts as malaria vector.
Behavior
Breeding is in marshes, ponds and water with grassy or floating
vegetation and rice fields. Adults draw blood from humans and
animals both indoors and outdoors, but adults rest outdoors after
feeding. This species is especially active in Egypt.

10. • Anopheles sergentii
Anopheles sergentii is often referred to as the “desert malaria
vector” in northern Africa, the Mediterranean basin and the Middle
East.
Life cycle
Life stages is Like all mosquitoes, anophelines go through four stages
in their life cycles: egg, larva, pupa, and imago. The first three
stages are aquatic and together last 5–14 days, depending on the
species and the ambient temperature. The adult stage is when the
female Anophebehaviles mosquito acts as malaria vector.
Behavior
hey inhabit borrow pits, rice fields, seepage waters and slow-
flowing streams and both sunny or partially shaded habitats. Adults
draw blood from humans and animals indoors and outdoors, but
rest in houses and caves after feeding.

11. Insect Behavior and Activity
Insect Behavior
Insect behavior is critical for successfully managing stored-product insect pests, particularly in the current climate where
more-targeted IPM programs are becoming more widely used. IPM relies on a fundamental understanding of pest behavior
and its implications for ecological parameters such as spatial distribution and population dynamics.
One of definition of behavior is any action that an individual carries out in response to a stimulus or its environment,
especially an action that can be observed and described. However, insects also behave spontaneously, in the absence of any
obvious stimulus. Thus, behavior includes studies to understand how an insect takes in information from its environment,
processes that information, and acts. Processing information in the central nervous system may involve integrating
information over time, including stimuli such as hormones coming from within the insect. Thus, the connection
between stimulus and response can be delayed and indirect.
The genetic analysis of behavior rightfully has been perceived to be more complex than analysis of morphological or
anatomical traits (Vanin et al., 2012). One complication in genetic analyses of behavior is the difficulty in defining the
behavior in a clear manner. Often “a behavior” may consist of multiple components, which can lead to confusion regarding
the number of genes involved. Distinguishing between behavior and physiology can be particularly difficult. The same
behavior can be examined from at least four different viewpoints:
(1) the immediate cause (or control);
(2) its development during the individual’s lifespan;
(3) the function of the behavior; and
(4) how the behavior evolved (Wyatt, 1997).

12. Insect activity
Insect activity influences the behavior in wild range .including
• Locomoting
• Grooming
• Feeding
• Communicating
• Reproductive
• Dispersal/ migration
• Hand prey selection
• Diapause and various responses to environmental hazards