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ENVS 2210 (46)
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Department
Environmental Sciences
Course
ENVS 2210
Professor
Ernesto Guzman
Semester
Winter

Description
ENVS Unit 04: Growing Up to Be a Bee - Holometabolous insects go through four main stages: egg, larva, pupa, adult go through dev in predictable time course - Embryo dev in egg then hatches into larva (feeding machine), stops eating then pupates and experiences metamorphoses into adult bee o Metamorphosis = quicker for queen, slower for worker, slowest for drone…this is b/c of nutrition - Hormones control transformations of insects, hormones keep larvae young, signal to exoskeleton to dissolve/regrow - Worker bees tasks: stay in hive, attend to needs of larvae the queen and comb o Most die away from home and among the flowers Chapter IV-12: From Egg to Adult - Queen normally lays eggs in colony of honeybees, but some exceptions - Queen lays egg into comb by inserting her abdomen into cell bottom and it will either be fertilized or wont o She could fertilize an egg by freeing a few sperm from her spermathecal duct - Sperm finds micropyle on egg which is a small hole to enter and it will reach the egg nucleus floating in the yolk - Even if egg nucleus is fertilized or not, it divides o Division arranges in layer if cell (blastoderm), and folds into forming the embryo - After 3 days as egg, embryo shows head w/ buds for mouthparts and antennae, then over 6 days the larva will grow 1 500 times in weight o Goes through 5 larval stages:  Head gets main mouthparts  Body cavity contains haemolymph  Intestine exits through anus  Only purpose of larva is to eat and grow, fed by workers - After 6 days larva occupies entire cell and stops feeding, then spins cocoon of silk gland silk o Larva starts metamorphosis with cocoon - Metamorphosis, head becomes for recognizable, abdomen dev form and genetalia (ovipositor/sting in queens and workers, endophallis in drones. - After 12 days as pupa, worker bee is ready to be adult and breaks out of larval cuticle (chews way out of cocoon, emerge as callow) - Holometabolous is form of insect development from egg to larva to pupa to adult o This dev in honeybees differs in duration btwn castes (76) Chart of characteristic differences btwn Workers, Queen and Drones page 77 Chapter IV-13: Nutrition - Nutrition process where organism gets energy from enviro to maintain growth, maintenance, repro, and activities - Heterotrophic rely on organic food sources for minerals needed (need protein, carb, minerals, fats, vitamins, and water) - Honeybees are herbivorous heterotrophs, get nutrients from plants (nectar and pollen) or the occasional honey dew, or oil from special flowers - Pollen, chemically complex o 25% protein o 10% amino acid o 25% carbohydrates o Remaining is lipids, enzymes, pigments, vitamins, sterols o SOOO entire nutrition can come from pollen - Nectar sugary liquid/syrup, transformed into honey - Sugars fuel for activity o Sugars are building blocks of carbs, CH 0: 2imple sugars are monosaccharaides like glucose or fructose (cannot be broken down further) - Enzymes are molecules for digestion - Bees break down carbs to build complex molecules that are part of exoskeleton, internal organs, bees wax, hormones, and pheromones - Proteins used by honeybees comes form pollen o Large complex molecules built from amino acids joined by peptide bonds o Proteins must be digested and broken down by enzymes (proteases) then go through haemolymph to body parts o 10 amino acids essential for proper honeybee growth 1. Arginine 2. Histidine 3. Lysine 4. Tryptophan 5. Phenylalanine 6. Methionine 7. Threonine 8. Leucine 9. Isoleucine 10. Valine - Little known about nutritional needs of lipids in honeybees o Require fatty acids, sterols (cholesterol) and phospholipids in their diets  Cholesterol necessary for production of moulting hormone during growth and dev o Dietary source of most lipids = pollen, but also some nectars o Nectar used as precursor to body fat - Require vitamins in diet, vitamins=micronutrients, MUST come from diet o Vitamins classified as fat-soluble (A, D, E, K) or water-soluble (B complex, C) o Co-enzymes important in metabolism and interaction w/ enzymes contain vitamins as part of o Bees need B-complex vitamins and vit C for normal brood rearing - Minerals found in pollen: Potassium, sodium, phosphorus, calcium, magnesium, copper, manganese, zinc, iron - Honeybees able to fulfill dietary need for mineral w/ pollen, nectar and water - Water essential b/c lose it through feces, sweat o In winter they are stuck in hive and must have enough water to breakdown sugars from honey and pollen Larval and Queen Nutrition - Larvae and queen fed by workers, have huge requirements - Brood food/royal jelly produced by hypopharyngeal and mandibular glands of young nurse bees o Two components: clear protein-full liquid from hypopharyngeal glands and white oily material from mandibular gland secretions o Mostly water (60-70%), dry weights made of: 17-45% protein, 18-50% sugars, 4-19% lipid, 2-3% minerals  Highly nutritious and fed to all larval bees  Larvae that are becoming queens are fed royal jelly throughout immature lives, but larvae workers and drones only fed royal jelly mixed with honey, pollen and water - Rate of food intake regulates activity of corpora allata and high levels of juvenile hormone in body of developing larva - Progressive provisioners (honeybees and bumblebees) b/c provide larval w/ food needed Diff types of Larval Food and Feeding Methods Used in Rearing the Three Castes of Honeybees: Castle Larval Queen Larval Worker Larval Drone Larval Food Royal jelly Royal or perhaps Diff composition worker jelly but from royal jelly mixed w/ pollen and honey Type of Sugar Glucose is maj Mix of sugars Mix of sugars Feeding Methods Heavy feeding of Light feeding Receive more food royal jelly than workers Chapter IV-14: Hormones - Dynamic equilibrium maintained among hormones - Hormones bond w/ specific plasma that prevent them from degenerating prematurely o Keep hormones from becoming absorbed by tissues they affect (target tissues) - Insects (honeybees) two most important hormones are: o Moulting hormone (M.H.) that’s secreted from prothoracic glands  Growth requires moulting b/c exoskeleton shed and need to expand, during metamorphosis/structural changes  Metamorphosis controlled by hormonal interplay o Juvenile hormone (J.H.) secreted by the corpora allata - Insects of subclass holometabola: Bees, flies, butterflies and moths, and beetles have greatest body differentiation from egg to adult, and complete metamorphosis so their life cycle has four stage: egg, larva, pupa, adult - Other insects Hemimetabola undergo incomplete metamorphosis going from egg to nymph and then to adult o Nymphs are like adults but w/o winds and genitalia o In the subclass ametabola, the insects never developed wings and change little except from size, from egg to adulthood Hormonal Regulation in Insects - Chemi
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