aster2 (version 0.2-1)

hornworm: Life History Data on Manduca sexta

Description

Data on life history traits for the tobacco hornworm Manduca sexta

Usage

data(hornworm)

Format

An object of class "asterdata" (see asterdata) comprising records for 162 insects (54 female, 68 male, and 40 for which there was no opportunity to determine sex) observed over 40 days. Nodes of the graph for one individual are associated with the variables (levels of the factor hornworm$redata$varb) in dependence groups

P

Bernoulli. Predecessor 1 (initial node). Indicator of pupation.

T330, T331, T332

Three-dimensional multinomial dependence group. Predecessor P.

T330

Indicator of death after pupation. In these data, all deaths after pupation are considered to have happened on day 33 regardless of when they occurred (because the actual day of death was not recorded in the original data).

T331

Indicator of survival to day 33 but still pre-eclosion.

T332

Indicator of eclosion (emergence from pupa as adult moth on day 33.

B33

Zero-truncated Poisson. Predecessor T332. Count of ovarioles on day 33. Only females have this node in their graphs.

Tx1, Tx2

For x = 34, ..., 40. Two-dimensional multinomial dependence group. Predecessor Tw1, where w = x - 1.

Tx1

Indicator of survival to day x but still pre-eclosion.

Tx2

Indicator of eclosion (emergence from pupa as adult moth on day x.

Bx

Zero-truncated Poisson. Predecessor Tx2. Count of ovarioles on day x. Only females have these nodes in their graph.

Covariates are

Sex

a factor. F is known female, M is known male, U is unknown (no opportunity to observe).

Time_2nd

time (in weeks) to reach the 2nd instar stage. Larval instars are stages between molts (shedding of exoskeleton) of the larval form (caterpillar).

Mass_2nd

mass (in grams) at the 2nd instar stage.

Mass_Repro

mass (in grams) at eclosion.

LarvaID

name of an individual in the original data.

Source

Joel Kingsolver http://bio.unc.edu/people/faculty/kingsolver/

Details

This is the data described by and analyzed by non-aster methods by Kingsolver et al. (2012) and re-analyzed using this package by Eck et al. (submitted).

For an illustration of the graph, see Figure 1 in Eck et al. (submitted).

In the description above, a concrete example of the x and w notation is that T351 and T352 form a two-dimensional multinomial dependence group, the predecessor of which is T341, and B35 is a dependence group all by itself, its predecessor being T352.

Every multinomial dependence group acts like a switch. If the predecessor is one, the dependence group is multinomial with sample size one (exactly one variable is one and the rest are zero). So this indicates which way the life history goes. If the predecessor is zero, then all successors are zero. This goes for all variables in any aster model. If Tx2 is zero, then so is Bx. The ovariole count is zero except for the day on which the individual eclosed.

References

Kingsolver, J. G., Diamond, S. E., Seiter, S. A., and Higgins, J. K. (2012) Direct and indirect phenotypic selection on developmental trajectories in Manduca sexta. Functional Ecology 26 598--607.

Eck, D., Shaw, R. G., Geyer, C. J., and Kingsolver, J. (submitted) An integrated analysis of phenotypic selection on insect body size and development time.

Examples

data(hornworm)
names(hornworm)
names(hornworm$redata)
levels(hornworm$redata$varb)