lectures 11 and 12

lectures 11 and 12 - Weeks 11 & 12: Animal Courtship...

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COURTSHIP GIFT GIVING: MOST COMMON IN SMALL PREDATORY ANIMALS EXAMPLES : SOME SPIDERS, DANCE FLIES, SCORPIONFLIES REAL RISK FACED BY AMOROUS MALES – MAY BE MISTAKEN FOR FOOD. MALES GIVE FEMALE A GIFT OF FOOD . KEEPS HER OCCUPIED ; GIFTS CAN ENTICE A FEMALE TO ACCEPT A MATE AND TO KEEP THE SUITOR ALIVE . OTHER WAYS OF AVOIDING BEING A MEAL DURING COURTSHIP: M ALE ORB-WEAVER SPIDERS ARE OFTEN MINISCULE (TINY) COMPARED TO THE FEMALE; THEY MAY ALSO PLUCK THE FEMALE’S WEB WITH A SPECIAL NUPTIAL RHYTHM TO ENSURE THEY ARE NOT MISTAKEN FOR FOOD. RISKS OF COURTSHIP : 1. MIGHT BE EATEN BY POTENTIAL MATE 2. GREATER EXPOSURE TO PREDATORS (MORE VISIBLE TO THE EYE AND EAR) 3. USE UP TIME THAT COULD BE USED TO FIND FOOD 4. ADVERTISEMENTS EXPENSIVE (SONG, APPEARANCE, BEHAVIOUR, CHEMICALS) 5. AFTER EXPENDING ENERGY, THE MALE STILL MIGHT GET TURNED DOWN 6. AFTER SPENDING ENERGY, THERE IS NO GUARANTEE OF PATERNITY THE MALE COULD BE EXPLOITED BY A CHEATER (A SNEAKER OR SATELLITE MALE) - SATELLITE MALES IN FROGS, CRICKETS MOST COMPLEX CHEATER STRATEGY IS IN BLUEGILL SUNFISH: THREE FORMS OF MALE 1) BIG COLOURFUL, NEST BUILDER FORM: ATTRACTS FEMALES 2) SMALL JUVENILE-MALE FORM: IGNORED BY THE LARGE MALE YET SNEAK IN AND DROP THEIR SPERM ON THE FEMALE’S EGGS 3) FEMALE FORM: FEMALE FORM DROPS IN DURING COURTSHIP, MALE THINKS HE HAS TWO FEMALES AND THE FEMALE MIMIC DROPS SPERM ON REAL FEMALE’S EGGS WHY THESE FORMS? ALL HAVE SOME DEGREE OF SUCCESS IN ORDER TO PERSIST IN POPULATION CUCKOLDRY = GENETIC ROBBERY – WHEN A MALE BREEDS WITH ANOTHER MALE’S MATE AND FATHERS SOME OF HER OFFSPRING. ATTEMPTS TO GUARANTEE PATERNITY OF OFFSPRING: 1) REMOVE COMPETITOR’S SPERM AND REPLACE IT WITH YOUR OWN EXAMPLE: EBONY JEWELWING DAMSELFLY PENIS HAS SCOOPS TO PULL OUT OTHER MALE’S SPERM 2) STAY WITH FEMALE UNTIL NO LONGER MATES OR EGGS ARE LAID = CONTACT GUARDING EXAMPLES: BULL MOOSE, SOME DRAGONFLIES DO BY: A) CLASPERS STAY ATTACHED TO FEMALE’S HEAD WHILE SHE LAYS HER EGGS B) EASTERN PONDHAWK MALE FLIES IN CIRCLES AROUND FEMALE WHILE SHE LAYS HER EGGS 3) HAVE VERY LONG COPULATIONS - WOLVES STUCK TOGETHER FOR MORE THAN ONE HOUR; MARCH FLIES – 56 HOURS SOME ANIMALS USE SPECIAL TOOLS TO MAKE SURE FEMALE DOESN’T STRAY: MALE
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WALKING STICK USES CLASPERS (LIKE HANDCUFFS) TO KEEP FEMALE ATTACHED UNTIL SHE IS FINISHED MATING – NO OTHER MALE CAN INTERRUPT. COPULATIONS LAST DAYS – ONE SPECIES TEN DAY COPULATION ! 4) COPULATORY PLUG = CHASTITY BELT MADE BY SEALING FEMALE'S SEXUAL OPENING WITH A) HEADLESS SPERM MANY BEETLES - LOTS PRODUCED, FORM PHYSICAL PLUG B) GIANT SPERM FEATHERWING BEETLE – SPERM IS 2X ITS BODY LENGTH , THE TAIL ACTS AS PLUG C) CEMENT PLUG: 1) MOLES MAKE EPOXY WITH TWO COMPOUNDS IN SPECIAL GLAND 2) MOSQUITO EJACULATE HARDENS TO CEMENT, ALSO CONTAINS
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lectures 11 and 12 - Weeks 11 & 12: Animal Courtship...

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