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 & Reproduction2 separate processesFeeding Rate is related to body sizeConverts food to offspringTemp and body size growth/ reproduction correlatesEarthwormEisenia venetaL. 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 HistoryMating 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 hermaphroditicThey 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 corneusAfter 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 plantThree reproductively isolated subspecies of Arisaema; triphyllum is most commonTetraploid with 56 chromosomesSexual reproductionTrue dioecious plant, flowers are unisexual;When plant is young and small, flowers are male.As the plant ages and grows, the male flowers dieand female flowers mature.This prevents self pollination.
6 Jack-in-the-pulpit : Arisaema triphyllum Flowers from April to JunePollinated by flies, which are attracted by smellFertilized flowers develop into a cluster of berries, which start out green and then turn red; fruit ripens late summer and fallEach berry produces 1-5 seedsSeedlings 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 DimorphismMales “sing” from trees -vibrating abdominal membranes to attract mates, females are muteair sacs in male’s abdomen amplify the song, digestive and reproductive organs are reducedMales detect the closeness of competing males (opercula)Females can detect direction of sound (track the singing males)
8 Dog Day Cicada (Tibicen canicularis) LifecycleEgg (haploid gametes->diploid)2 monthsLaid in twigs so they can hatch then burrowNymphDog Day is annual (but also year periodical cicadas)Sap from xylemDevelopment completed undergroundAdultEmerge from exoskeletonReproduce then die
9 Melanoplus - Grasshopper Sex: male and femaleFemales produce eggs – internally fertilizedMales produce spermatophoreFemale grasshoppers lay eggs in soil – production areasLay eggs throughout autumn into September and OctoberFemale can lay up to 25 eggsEggs remain in soil over winter and begin to hatch in springNymphs molt five times and reach adulthood in 60 daysIdentify species through inspecting male genetaliaDifferent species lay eggs on different plants and hatch at different times
10 The Nitty GrittySpermatophore forms in ejaculatory duct once pair is coupledTakes five minutes to fully formedUp to 14 in one copulationNutrients from spermatophore incorporated into eggsPolygynandric mating systemFemales with more mates →more nutrients from ejaculate transfer → higher fecunditySecond males → egg pods produced and deposited more frequentlyEjaculate is a mating effort, not insurance of paternityMales insure paternity through frequent and extended copulationRisk of predatorsCardero, 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 antNupital flight: winged males and females mate while flyingmales die, females lose wings and become new queensQueens lay eggs who will become her workers as adultsQueens wait in chamber during this time, using fat reserves and wing muscle as energy sourceTotal lifespan: 6-12 weeks.Can be increased for up to 10 months if coldAfter 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 HaplodiploidyMales are haploid and develop from unfertilized eggsFemales are diploid and develop from fertilized eggsFemales 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