DIAPAUSE

QUISENCE VS. DIAPAUSE 1. BOTH ARE STATES OF ARRESTED GROWTH 2. QUIESENCE IS AN IMMEDIATE RESPONSE TO AN UNFAVORABLE ENVIRONMENTAL FACTOR 3. DIAPAUSE IS MUCH MORE SUBTLE, AS IT IS NOT AN IMMEDIATE RESPONSE

FACULTATIVE VS. OBLIGATORY DIAPAUSE 1. INSECTS HAVING FACULTATIVE DIAPAUSE MAY GO THROUGH SEVERAL GENERATIONS WITHOUT SHOWING DIAPAUSE – MULTIVOLTINE 2. INSECTS HAVING OBLIGATORY DIAPAUSE HAVE A DIAPAUSE IN EACH GENERATION - UNIVOLTINE

DIAPAUSE CAN OCCUR IN ANY LIFE STAGE SPECIES DIAPAUSE STAGE TETANOCERA ANNAE PUPA (OBLIGATORY) FERRUGJNEA PUPA (FACULTATIVE) T. PLEBEJA PUPA (FACULTATIVE) T. LOEWI ADULT, EGG T. VICINA MATURE LARVA

EGG DIAPAUSE IS OF TWO TYPES 1. TRUE EGG DIAPAUSE - EMBRYONIC DEVELOPMENT STOPPED DUE TO PRESENCE OF AN EGG-INHIBITING HORMONE 2. FALSE EGG DIAPAUSE – EMBRYO DEVELOPS BUT FAILS TO HATCH. REALLY A FIRST-INSTAR LARVAL DIAPAUSE (NO ECDYSONE)

LARVAL AND PUPAL DIAPAUSE CAUSED BY FAILURE OF SECRETION OF ECDYSONE

ADULT DIAPAUSE CAUSED BY FAILURE OF REPRODUCTIVE ORGANS TO MATURE AND PRODUCE GAMETES DUE TO ABSENCE OF A GONADOTROPHIC HORMONE

PHOTOPERIOD (DAY LENGTH) USUALLY CAUSES FACULTATIVE DIAPAUSE 1. LONG-DAY INSECTS 2. SHORT-DAY INSECTS

ENDOCRINE GLANDS INVOLVED IN DIAPAUSE 1. NEUROSECRETORY CELLS IN PROTOCEREBRUM – “BRAIN” HORMONE 2. CORPORA CARDIACA – STORES AND RELEASES BRAIN HORMONE 3. PROTHORACIC GLANDS – PRODUCES AND RELEASES ECDYSONE 4. SUBESOPHAGEAL GANGLION – PRODUCES AND RELEASES EGG DIAPAUSE HORMONE

PHYSIOLOGICAL CHARACTERISTICS OF A DIAPAUSING STAGE 1. METABOLIC ACTIVITY DRAMATICALLY REDUCED 2. OXYGEN UPTAKE CURTAILED 3. BRAIN LOSES ELECTRICAL ACTIVITY 4. CYTOCHROMES IN CELLS REDUCED