Revision as of 10:40, 16 October 2016

Model

Simulation of gene circuits

Epidemic

B. dorsalis is a major cause of annual agricultural losses due to oviposition in fruits. Here we introduce our prototype trap and M. anisopliae, our genetically engineered fungi, to address this issue.
Our model aims to demonstrate that combining our prototype with the fungi can reduce B. dorsalis’ population. We selected the SEIR model, which fits the ideal assumption in epidemiology, and revised the model to make it more practical for our purpose.

Symbol	Description
Susceptible	B. dorsalis is slightly or moderately resistant to M. anisopliae
Exposed	B. dorsalis is exposed to a low amount of M. anisopliae in our trap; disease will be spread further during mating.
Infected	M. anisopliae enters B. dorsalis’ hemolymph and initiates cell division.
Death	B. dorsalis dies from the infection of M. anisopliae.

Based on our assumptions, we developed a set of differential equations that characterizes the nature of epidemic in our model:
dms/dt=daily_move_in-trap-death_rate*ms
dfs/dt=daily_move_in-death_rate*fs

Parameter

Parameter

Type	Name	Meaning (Value)	Reference
Constant	Mating　rate	0.8635
	daily_capture	40
	daily_move_in	0
	K	adult death rate (0.05)	[1]
	k0	larval death rate (0.23)	[2]
Variable	ms	susceptible male
	Fs	susceptible female
	me	exposed male
	Fe	exposed female
	mi	infected male
	Fi	infected female
	D	Death

Result

The graph above shows an initial growth in population due to the attraction of B. dorsalis from the environment. However, the population subsequently drops when infected by M. anisopliae. The results indicate that the use of prototype combined with the fungi yields a 70% decrease in the B. dorsalis population. Thus, we can put our product into practice a few weeks prior to the harvest to minimize crop damage.

Reference

1.Life History and Demographic Parameters of Three Laboratory-reared Tephritids (Diptera: Tephritidae)
2.Effect of temperature on the development and survival of immature stages of the carambola fruit fly, Bactrocera carambolae, and the Asian papaya fruit fly, Bactrocera papayae, reared on guava diet