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Earthworm Hermaphrodites Both Female & Male Life Span 1-8 years

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Presentation on theme: "Earthworm Hermaphrodites Both Female & Male Life Span 1-8 years"— Presentation transcript:

1 Earthworm Hermaphrodites Both Female & Male Life Span 1-8 years
Copulation & Reproduction 2 separate processes Feeding Rate is related to body size Converts food to offspring Temp and body size growth/ reproduction correlates Earthworm Eisenia veneta L. Fayolle, H. Michaud, D. Cluzeau, J. Stawiecki, Influence of temperature and food source on the life cycle of the earthworm Dendrobaena veneta (Oligochaeta), Soil Biology and Biochemistry, Volume 29, Issues 3–4, March–April 1997, Pages

2 Earthworm Eisenia veneta
Life History Mating occurs on the surface, often at night. During Copulation: the worms overlaps their front ends ventrally and exchange sperm with one another. Some time after copulation, the worm creates a ring around its self and injects its own eggs and the sperm into it. The ring end of seals and becomes a cocoon. Several days later, a small but fully formed earthworm emerges days to develop. T. Jager, S.A. Reinecke, A.J. Reinecke, Using process-based modelling to analyse earthworm life cycles, Soil Biology and Biochemistry, Volume 38, Issue 1, January 2006, Pages 1-6, ISSN ,

3 The Orb Snail ( Planorbidae corneus)
Orb snails are hermaphroditic They mate sexually or self fertilize many times in their life cycle. During copulation, each snail passes sperm to the other snail. The spermazoa travel down the oviduct and are stored in the bursa copulatrix. That sperm does not necessarily fertilize the eggs because both snail’s sperm are passed down the ovaduct towards the eggs. Self fertilization is limited in that the offspring are less viable without genetic recombination

4 Planorbidae corneus After fertilization, the snails lay their eggs in a gelatinous mass in a damp area. FUN FACT: Snails do not follow Mendel’s principles of inheritance. Instead they exhibit the phenomena of maternal inheritance in the trait of shell coiling. Female cytoplasm contains the mitochondria, which is always inherited by the offspring. The cytoplasm in snails contains the gene for the direction of shell coiling. The phenotype of the mother will ALWAYS be expressed in the offspring, even if the males have the dominant trait.

5 Jack-in-the-pulpit : Arisaema triphyllum
Herbaceous perennial plant Three reproductively isolated subspecies of Arisaema; triphyllum is most common Tetraploid with 56 chromosomes Sexual reproduction True dioecious plant, flowers are unisexual; When plant is young and small, flowers are male. As the plant ages and grows, the male flowers die and female flowers mature. This prevents self pollination.

6 Jack-in-the-pulpit : Arisaema triphyllum
Flowers from April to June Pollinated by flies, which are attracted by smell Fertilized flowers develop into a cluster of berries, which start out green and then turn red; fruit ripens late summer and fall Each berry produces 1-5 seeds Seedlings need 3+ years of growth before they are big enough to flower

7 Cicadas Kristin Heslep
Sexual reproduction (m/f) Mate for 3-5 days (male clasper) Fertilized eggs laid in slits of twigs that the female makes with her ovipositor (400 eggs in 40 sites) Sexual Dimorphism Males “sing” from trees -vibrating abdominal membranes to attract mates, females are mute air sacs in male’s abdomen amplify the song, digestive and reproductive organs are reduced Males detect the closeness of competing males (opercula) Females can detect direction of sound (track the singing males)

8 Dog Day Cicada (Tibicen canicularis)
Lifecycle Egg (haploid gametes->diploid) 2 months Laid in twigs so they can hatch then burrow Nymph Dog Day is annual (but also year periodical cicadas) Sap from xylem Development completed underground Adult Emerge from exoskeleton Reproduce then die

9 Melanoplus - Grasshopper
Sex: male and female Females produce eggs – internally fertilized Males produce spermatophore Female grasshoppers lay eggs in soil – production areas Lay eggs throughout autumn into September and October Female can lay up to 25 eggs Eggs remain in soil over winter and begin to hatch in spring Nymphs molt five times and reach adulthood in 60 days Identify species through inspecting male genetalia Different species lay eggs on different plants and hatch at different times

10 The Nitty Gritty Spermatophore forms in ejaculatory duct once pair is coupled Takes five minutes to fully formed Up to 14 in one copulation Nutrients from spermatophore incorporated into eggs Polygynandric mating system Females with more mates →more nutrients from ejaculate transfer → higher fecundity Second males → egg pods produced and deposited more frequently Ejaculate is a mating effort, not insurance of paternity Males insure paternity through frequent and extended copulation Risk of predators Cardero, Carlos. “Ejaculate substances that affect female insect reproductive physiology and behavior: Honest or arbitrary traits?” Journal of Theoretical Biology, 1995, 4: Carothers, Eleanor E. “Notes on the taxonomy, development and life history of certain Acrididae (Orthoptera).” Transactions of the American Entomological Society, 1923, 49:7-24. Mardo, M.C. et. al. “Female fitness is increased by frequent mating in grasshoppers.” The Genetical Society of Great Britain, 1995, 74: Pickford, R. and Gillott, C. “Insemination in the migratory grasshopper, Melanoplus sanguinipes.” Canadian Journal of Zoology, 1971, 49:

11 Camponotus pennsylvanicus
Commonly known as the black carpenter ant Nupital flight: winged males and females mate while flying males die, females lose wings and become new queens Queens lay eggs who will become her workers as adults Queens wait in chamber during this time, using fat reserves and wing muscle as energy source Total lifespan: 6-12 weeks. Can be increased for up to 10 months if cold After about 2 years of colony growth, the queen begins to produce winged males and females to mate and start colonies of their own.

12 Camponotus pennsylvanicus
Haplodiploidy Males are haploid and develop from unfertilized eggs Females are diploid and develop from fertilized eggs Females are more closesly related to their sisters (r>0.75) than to their offspring (r=0.5) Workers are sterile, and exhibit altruism because of the high degree of relatedness to the rest of the colony

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