DATA SET IDENTIFIER: Leaf miners (Acrocercops sp.)larvae performance on young leaves of Manilkara bidentata

PROJECT TITLE: Herbivory

PROJECT DESCRIPTION: Long-term experiments associated with herbivory, a process which under certain circumstances may be an important regulator of detrital processing, has started at El Verde only since 2002. In addition to continuing long-term vegetation measurements will be conducted to determine long-term patterns of herbivory in two ways. As in most tropical forests, herbivores mainly eat young leaves (Coley & Barone 1996), which flush during May and June in the tabonuco forest or following disturbance (Angulo-Sandoval & Aide 2000). We will measure percent herbivory on new leaves of focal species marked each year in May and June. The second measurement will be of inputs of green leaf litter and insect frass to the forest floor. These measures will be used to gauge the changes in rates of herbivory during recovery from disturbance, with the ultimate goal of evaluating the role of herbivory in succession.

In addition, herbivory manipulations (autotroph-based food web) will be conducted within the main treatments of the Canopy Trimming Experiment. This experiment will employ small-scale mesocosms and removal of organisms to isolate the potential effects of food web components thought to influence ecosystem processes. Because of the intense maintenance requirements of these manipulations, they will be conducted for only two years.

Currently the following cross-site project is conducted at LUQ: "Canopy herbivory and soil processes in a temperate and tropical forest".

Three short term experiments have been conducted at Luquillo on herbivory: one to determine the importance of food availability on herbivory, leaf phenology and leaf damage; another to dermine the effect of group feeding for a specific species, and a last one to determine the effect of plant density on herbivory.

LTER CORE AREAS: (Annotate all that apply)

Population Dynamics

LEF LTER 1 RESEARCH TOPIC: (Annotate all that apply)

Disturbance regime

DATA SET FILES (SUBSETS):

We define a data file as a component of a data set. A data set can have only one data file or more. Basically, different data files have different data structures or format.

Data File No.	Data File Identifier	On-Line Filename	Starting Date	Periodicity of sample	End Period
1	Leaf miners (Acrocercops sp.)larvae survivorship on young leaves of Manilkara bidentata	larvaesurv.txt	April 1, 1995	monthly	March 31, 1996

RESEARCH LOCATION: Hurricane Recovery Plot (Big Grid) at El Verde

INVESTIGATORS:

PRINCIPAL INVESTIGATORS E-MAIL address

María del Pilar Angulo	manilkara1@hotmail.com
Mitchell Aide	maide@upracd.upr.clu.edu

OTHER RESEARCHERS E-MAIL address

CONTACT PERSONS E-MAIL address Phone Number (Include area code)

Mitchell Aide

maide@upracd.upr.clu.edu

(764-0000, Ext. 2580)

SOURCE OF FUNDING (SPONSOR): NSF-LTER

DATA SET ABSTRACT: Manilkara bidentata is attacked by a specialist leaf miner(Acrocercops sp.(microlepidoptera:gracillariidae).  More than one larvae can be found per mine within a leaf. The purposes of this study is to determine the effect of group feeding for this species since larval density within a leaf vary from 1-14 larvae per mine (Angulo-Sandoval personal observation). This variation allows to determine the effect of larval density on the amount of leaf damage, larval survivorship and larval growth. Leaves with mines varied in area from 10 to 224 cm² (mean = 85.7 cm²) and the number of larvae per leaf ranged from 1 to 14 (mean = 5.7 larvae/mine). There was no relation between the size of the leaf and the number of larvae found within the leaf.

There was a relationship between the number of larvae in a blotch mine and amount of damaged tissue. Herbivory increases from approximately 10% for one larva per leaf to 50% in leaves with eight larvae. In leaves with more than eight larvae, herbivory decreased . There was an effect of initial larval density on percent larval survivorship.Survivorship was high (70%) in leaves with one to three larvae. In intermediate density (4-8 larvae per mine) 50% of larvae survived and in high densities (9 - 14 larvae per mine), only 22% survived. Even though there was a decrease in larvae number in high densities, the final number of larvae remained higher, compared with low or intermediate densities. A linear relationship was found between number of larvae present in the leaf and the time it took the larvae to complete their larval stage. Larvae in high density (> 9 larvae per mine) tended to develop faster (3-8 days) than larvae in low densities (5 - 10 days). Larval size upon emergence ranged from 8 to 12 mm (mean= 9.27) but there was no effect of larval density on the final larval size. The total number of surviving larvae varied according to the initial larval number and was highest in mines with eight individuals of which on average 4.7 survived. The number of surviving larvae was less than three for all other clutch sizes. Even though eight larvae appears to be the optimum clutch size, most females produced smaller clutches (4- 6 larvae per leaf).All larvae that emerged built a cocoon and 90% emerged as butterflies.

DATA SET METHODS: Study area. The study was conducted in a 16 hectare plot, in the Luquillo Experimental Forest (LEF), within the Caribbean National Forest in northeastern Puerto Rico (180^o 20' N, 65^o 49' W)(Waide and Reagan 1996). The study area is near El Verde Research Station (350 m) on the northwest slope of the LEF. The forest is classified as subtropical wet forest and the dominant tree species are Dacryodes excelsa, Prestoea montana, Casearia arborea, Inga laurina, Manilkara bidentata, and Sloanea berteriana (Zimmerman et al. 1994). Average height of the forest canopy is 20 m with few emergent trees (Waide and Reagan 1996). Mean annual precipitation is 3460 mm (McDowell and Estrada-Pino 1988), and although January to April is the period of lowest precipitation, monthly means are usually greater than 100 mm /month (Brown et al. 1983) and evapotranspiration is lower than precipitation throughout the year (Waide and Reagan 1996). Mean monthly temperatures range between 21-25^o C (Brown et al. 1983).

The 16 ha plot was established in 1990. The plot was divided in 20 x 20 m plots, and all plants greater than 1 cm in dbh were marked. The forest composition within the plot varied due to previous land uses. Land uses in the northern part of the plot included a coffee plantation, selective logging, charcoal production, and some areas were completely cut. The southern part of the plot received much less human impact and was mainly limited to some selective logging and charcoal production. Major human impacts were eliminated in the 1950's when this area was incorporated into the Luquillo Experimental Forest (García and Scatena 1994). These different land use patterns have affected the distribution of plant species in the forest. Some species are more common in the southern part of the grid (e. g. Manilkara bidentata ) whereas others are more common in the northern part (e. g. Casearia arborea) (Zimmerman, personal communication).

Study species

Manilkara bidentata (A. DC.) A. Chev. (Sapotaceae), is a dominant species in the LEF. It is a shade tolerant species and can grow to 30 m in height (Crow 1980). M. bidentata ranges from near sea level to 600 m and in the LEF it is mainly associated with Dacryodes excelsa, Sloanea berteriana and Buchenavia capitata (You 1991). M. bidentata can be found throughout the West Indies, Panamá, Colombia, Venezuela, Guianas, Perú, Ecuador and northern Brazil (Little and Wadsworth 1989).

The principal herbivore of M. bidentata is a microlepidopteran, Acrocercops sp., (Gracillariidae) (Davis personal communication). The larval stage is a leaf miner that feeds on young leaves and creates a blotch mine on the upper surface of the leaf. Larvae have two distinct forms and habits. The early sap-feeding stage has a flattened, apodal body and highly specialized mouthparts. Larvae continuously move the mouthparts to increase the size of the mine in the first few layers of subepidermal parenchyma cells without ingesting any solid tissue (Davis 1987). After 3 or 4 days larval morphology and behavior change. The larvae become cylindrical with a round head, chewing mouthparts and protolegs. During this period the larvae feed on palisade parenchyma cells and deposit frass throughout the mine and do not cross the midrib. Around day ten larvae stop feeding and emerge from the blotch mine and pupate. After 12-16 days the adult emerges (Opler 1974, Angulo- Sandoval personal observations). Adults are 1 cm long (Angulo-Sandoval personal observation) and are diurnal (Davis, personal communication). The eyes are red and the body is golden with brown spots on the front wings. The hind wings are very narrow and have hair-like projections (Angulo-Sandoval personal observation).

Data collection Number of larvae, leaf area and area damage were measured for 115 young fully expanded leaves of M. bidentata saplings. Leaf area and area damaged were measured using a plastic grid. To determine the relationship between leaf size and number of larvae, larvae were counted when mines were 1mm long. The relation between leaf size and number of larvae that initiated mines was estimated by using a linear regression. To determine the relation between number of larvae and damage, number of larvae when the blotch mine was initially built, was recorded. When the blotch mine was completed, damaged area was measured using a plastic grid, and percent herbivory was calculated. The relation between larval number and leaf damage was established by using a linear regression.

For a detailed study of larval survivorship, rate of development and time to complete larval stage, a total of 55 leaves were studied, 35 in the laboratory and 20 in the field. No differences in larvae behavior were observed between leaves left on the plant and leaves observed in the lab (Larval survivorship F = 1.07, P = 0.45, larvae survivorship size upon emergence F= 1.52, P = 0.27). Leaves were chosen when mines were approximately 1 mm long so that the initial larvae number could be determined. Observations were performed daily for leaves in the lab, and every two days for larvae in the field. In the laboratory larval number and size upon emergence from the mine were also recorded. Number of pupae and adults were counted and percent survivorship was estimated for these developmental stages. Initial larvae number was multiplied by survivorship to determine total larvae survivorship.

REFERENCES:
Brown, S., A. E. Lugo, S. Silander and L. Liegel. 1983. Research history and opportunities in the Luquillo Experimental forest. General Technical Report No. SO-44, U. S. Department of Agriculture Forest Service. Southern Experimental Station, New Orleans, Louisiana, USA.

Crow T.R. 1980. A rainforest chronicle: a 30-year record of change in structure and composition at El Verde, Puerto Rico. Biotropica 12:42-55

García-Montiel D., Scatena F.N 1994. The effect of human activity in the structure and composition of a Tropical forest in Puerto Rico. For Ecol Monogr 2:130-132

Little, E. L., R. O. Woodbury and F. H. Wadsworth. 1974. Trees of Puerto Rico and the Virgin Islands. Agricultural Handbook no. 449. U. S. Department of Agriculture, Forest Service, Washington, D. C. USA

McDowell, W. H. and A. Estrada-Pino. 1988. Rainfall at the LEF Field Station, 1964-1986. CEER-T-228. Center for Energy and Environment Research. Rio Piedras, Puerto Rico.

Nuñez- Farfán J., Dirzo R. 1988. Within-gap spatial heterogeneity and seedling performance in a Mexican tropical forest. Oikos 51:274-284

Opler P.A. 1974. Biology, ecology and host specificity of microlepidoptera associated with Quercus agrifolia (Fagaceae). University of California Press. Berkeley

Waide, R. B. and D. P. Reagan. 1996. The rainforest setting. Pages 1-16 in D. P. Reagan and R. B. Waide, editors. The food web of a tropical rainforest. The University of Chicago Press. Chicago, Illinois, USA.

You C. 1991. Population dynamics of Manilkara bidentata in the Luquillo Experimental Forest. Puerto Rico. Phd dissertation, University of Tennessee, Knoxville

Zimmerman J. K., Everham III E. M., Waide R. B., Lodge D. J., Taylor C. M., Brokaw N. V. L. 1994. Responses of tree species to hurricane winds in subtropical wet forest in Puerto Rico: implications for tree life histories. J Ecol 82:911-922

CROSS-REFERENCES (other data sets related to this one): LTERDBAS99: Herbivory of eight common species at El Verde from 1994 to 1996, LTERDB102: Leaf miners (Acrocercops sp.)larvae performance on young leaves of Manilkara bidentata, LTERDBAS103 : Effect of plant density and light availability on leaf damage in Manilkara bidentata

SAMPLE LOCATION:

STORAGE SITES: ITES Data Management DM-002, Drawer#?; Mitchell Aide Laboratory at Biology Departmen, Natural Science Faculty, University of Puerto Rico, NCN Building Of. 308.

INVESTIGATOR'S ASSIGNED KEYWORDS: herbivory, Manilkara bidentata, el verde, disturbance, Acrocercops sp, larvae density, group behavior

LEF LTER OFFICIAL KEYWORDS (See table): EL VERDE, TABONUCO, DISTURBANCE, HERBIVORY, PEER REVIEWED JOURNAL

PUBLICATIONS:
Angulo-Sandoval, P. and T. M. Aide. 2000. Effects of plant density and light availability on leaf damage in Manilkara bidentata (sapotaceae). Journal of Tropical Ecology.

Angulo-Sandoval, P. and T.M. Aide. Leaf phenology and leaf damage of saplings in the Luquillo Experimental Forest, Puerto Rico. Biotropica (in press)

DISSEMINATION: UNRESTRICTED

REASONS TO RESTRICT DATA IN THIS DATA SET BEYOND ITS TWO YEAR POLICY PERIOD*:

*WILL HAVE TO BE APPROVED BY LTER PRINCIPAL INVESTIGATORS: J. ZIMMERMAN, A. LUGO , D.J. LODGE

FILING
___ "File" copy only : Data Management will only file an electronic copy of the data file and its documentation
X "Enter" data on-line : Data Management will be in charge of entering the data on computer files (Contact Eda C. Meléndez)

SITES DESCRIPTIONS: The study was conducted in the Luquillo Experimental Forest (LEF), which is part of the Caribbean National Forest in northeastern Puerto Rico (Waide and Reagan 1996). The study area is near the El Verde research station (350 m) on Northwest slope of the LEF. The forest is classified as subtropical wet forest and the dominant tree species are Dacryodes excelsa, Prestoea montana, Casearia arborea, Inga laurina, Manilkara bidentata, and Sloanea berteriana (Zimmerman et al. 1994). The average height of the forest canopy is 20 m and there are few emergent trees (Waide and Reagan 1996). Mean annual precipitation is 3460 mm (McDowell and Estrada-Pino 1988), and although January to April is the period of lowest precipitation, monthly means are usually greater than 100 mm/month (Brown et al. 1983) and evapotranspiration is lower than precipitation throughout the year (Waide and Reagan 1996). Mean monthly temperatures range between 21-25^oC. (Brown et al. 1983).

Geographical positional system (GPS) Coordinates for each location:

location	latitude	longitude
Luquillo Experimental Forest (LEF)	180° 20' N	65° 49' W

VARIABLES (ATTRIBUTES):

FILE NAME OR #ABOVE (all in which the variable appears)	1	1	1
ABBREVIATION (as it appears on the data file)	larvae	size	days
NAME OF VARIABLE	Number of larvae per leave	Size of larvae	number of days inside the mine
DEFINITION OF VARIABLE	Number of larvae of Acrocercops sp on leaves of Manilkara bidentata	Size of larvae of Acrocercops sp upon emergence	Number of days of larvae of Acrocercops sp. inside mine
UNIT	number	millimeter	number
PRECISION		±0.1
RANGE OR LIST OF VALUES	1-14	8 - 12	5-10
DATA TYPE	integer	decimal	integer
MISSING DATA CODES	none	none	none

COMPUTATIONAL METHODS:

Variable Name	Formula

FOR DATA MANAGER USE ONLY

DATE OF LAST REVIEW: May 1, 2008
DATE OF LAST ENTRY: October 1996
STAGE OF DATA SET MANAGEMENT (dates):
RECEIVED 9 Sep 1998
ENTERED: FILED 10 Sep 1998 (?)
ON-LINE not until published
REVIEWED BY RESEARCHER 9 Sep 1998
FILING MEDIA:
NAME OF DOCUMENTATION FILE: lterdb99.fm*
NAME OF DATA FILE: herbivorlarva.wq1
NAME OF ON - LINE CATALOG: LTERDBAS RECORD # : 102
DOCUMENT TYPE: magnetic media
PRIORITY TO BE ENTERED: N/A

Rev. date of this form: 19 March 2002