Post on 15-Jun-2020
transcript
Development II: Endocrinology
Endocrine System in Insects
Regulation of Development in a Paurometabolous Insect
Regulation of Development in a Paurometabolous Insect
Regulation of Development in a Holometabolous Insect
Regulation of Development in a Holometabolous Insect
aRAIN CELLS
CARDIACUM
GLAND
,.(-.;;:) .... . -: ·< .):)·_\ (' CHROMOSOMES .'. '
\ ·.;).' +
t:-...·,/
'·" "\ RNA (Al ..<t ""< ...._,.. .· .·\ . _.. ......... . .•,...A. ·
PROTEIN SYNTHESI S
+ ADULT STRUCTURES
LARVA PUPA ADULT
FIGURE 21.12. Schematic reprsentatlon of endocrine control of development. [After L. l. Gilbert, 1964, Physiology of growth and development: Endocrine aspects, in: The Physiology of Insecto, 1st ed., Vol. I (M. Rockstein, ed.). By permission of Academic Press and the author.]
penultimate larval instar
Figure 5.8. Typical juvenile hormone titer profiles during the end of larval life of hemimetabolous and holometabolous insects. Hypothetical JH-sensitive peri- ods
are indicated by gray bars. In the Hemimetabola there is a JH-sensitive period near the end of each larval instar, during which the commitment to larval versus adult development is controlled. In the Holometabola there is a JH-sensi-
tive period for larval versus pupal determination near the end of each larval instar, except in the final larval instar. The two JH-sensitive periods in the final larval instar are based on the findings in Manduca sexta (fig. 5.7). There is an additional JH-sensitive period for pupal versus adult determination early in the
pupal stage, at the outset of adult development.
Hemimetabola LIA
penultimate larval instar final larval instar
epidermis
LIP
lmaglnaldisks epidermis
LIP P/A
epidermis P/A
final larval instar pupa adult
LIA
adult
Holometabola
Comparison of Development in Paurometabolous & Holometabolous Insects