DOI: 10.5061/dryad.69p8cz9dv
title: Data and code from: How a territorial challenge changes sex steroid-related gene networks in the female brain: A field experiment with the tree swallow

description: Territorial competition can stimulate secretion of testosterone (T), which
 is thought to act on neural circuits of aggression to promote further
 aggression. Here, we test the hypothesis that competition modulates sex
 steroid sensitivity and conversion in the brain, focused on the female
 tree swallow (Tachycineta bicolor). In this bird species, exogenous T
 enhances female aggression, but social competition for limited nesting
 territories does not stimulate systemic T elevation. We exposed
 free-living females to simulated territorial intrusions and sampled five
 regions of the vertebrate social behavior network (SBN). Using
 quantitative PCR, we measured mRNA abundance of: androgen receptor,
 5-alpha reductase, estrogen receptor alpha, and aromatase. Using standard
 analyses, we found essentially no treatment effect on mRNA abundance in
 any one brain area; however, network analyses revealed marked
 socially-induced changes in gene co-expression across the SBN. After a
 territorial challenge, gene expression was more positively correlated with
 T, and genes specific to the androgen-signaling pathway were also more
 positively correlated with one another. The challenged brain also
 exhibited stronger negative correlations among genes in the nucleus
 taeniae, but stronger positive correlations between the lateral septum and
 bed nucleus of the stria terminalis. Together, these findings suggest
 that, in response to female-female territorial challenges, T acts on
 androgen-mediated circuits of aggression, with some divergence in gene
 regulation in the nucleus taeniae. The post-transcriptional consequences
 of these shifts require more research, but their existence underscores
 insights to be gained from analyzing the neuroendocrine properties of the
 SBN using network-level perspectives.
description: # How a territorial challenge changes sex steroid-related gene networks in
 the female brain: A field experiment with the tree swallow Dataset DOI:
 [10.5061/dryad.69p8cz9dv](10.5061/dryad.69p8cz9dv) ## Description of the
 data and file structure This study was conducted on female tree swallows
 breeding in bird boxes in Linesville, PA, in spring 2019. Females were
 either exposed to a 30-minute simulated territorial intrusion (STI) or
 belonged to the control treatment group (n=10 each). Aggressive behavior
 was recorded during the first 5 minutes of each STI. 2 to 3 hours after
 the end of the STI, females were captured and collected for tissue
 samples. Circulating blood was collected for measuring testosterone
 concentrations (via a high-sensitivity ELISA kit- Enzo #ADI-900-176). Each
 female's whole brain was removed and flash-frozen on dry ice. Later,
 brains were microdissected to obain RNA from 5 nodes of the social
 behavior network: BnST= bed nucleus of the stria terminalis, LS= lateral
 septum, NT= nucleus taeniae, POA= preoptic area of the hypothalamus, VMH=
 ventral medial hypothalamus. qPCR was used to measure relative mRNA
 abundance for four genes of interest: androgen receptor, estrogen receptor
 alpha, aromatase, and 5-alpha reductase.  ### Files and variables ####
 File: data\_bird.csv **Description:** The data table is organized such
 that one row represents one female bird. Includes capture details and
 circulating T concentrations for all females, as well as behavioral
 measurements from birds in the STI treatment group ##### Variables *
 Female ID: unique identifier for each bird collected in the study *
 Treatment: STI (exposed to simulated territorial intrusion) or control *
 julian date: date of collection, as day of year (Jan 1= 1) * Capture_time:
 time of day when bird was captured and euthanized (hh:mm am/pm)  * Mass_g:
 body mass measured at time of capture/collection, in grams * ng T/mL
 plasma: circulating testosterone concentration (nanograms of T per
 milliliter of plasma), as measured via an ELISA from hormones extracted
 from blood plasma collected after decapitation * any agg 5s bins (1st
 5min): aggression score measuring how females in the STI treatment group
 responded to the simulated intruder; the number of 5-second time bins
 containing any aggressive behavior (see Bentz et al. *Ethology*, 2019) *
 STI_to_cap_h: latency from the end of the 30-minute STI to capture, in
 hours #### File: data\_br.csv **Description:** Data table is organized
 such that one row represents one biological sample on which qPCR was
 performed (i.e., one brain region). ##### Variables * Female ID: unique
 identifier for each bird collected in the study * Treatment: STI (exposed
 to simulated territorial intrusion) or control * brain region:
 microdissection region of the social behavior network; BnST= bed nucleus
 of the stria terminalis, LS= lateral septum, NT= nucleus taeniae, POA=
 preoptic area of the hypothalamus, VMH= ventral medial hypothalamus *
 Sample Name: unique identifier for each micro-dissected brain region from
 each individual * ct GAPDH: raw qPCR results (threshold cycle) for
 housekeeper gene GAPDH * ct PPIA: raw qPCR results (threshold cycle) for
 housekeeper gene PPIA * RQ 5aRed: relative quantification of 5-alpha
 reductase gene; calculated using the 2-∆∆CT method * RQ AR: relative
 quantification of androgen receptor gene; calculated using the 2-∆∆CT
 method * RQ AROM: relative quantification of aromatase gene; calculated
 using the 2-∆∆CT method * RQ ERa: relative quantification of estrogen
 receptor alpha gene; calculated using the 2-∆∆CT method #### File:
 George\_and\_Rosvall\_H\_B\_2025.R **Description:**  R script for
 reproducing statistical results and figures #### File: network\_layout.csv
 **Description:** X and y coordinates for each node of network graphs
 (Figure 4) ##### Variables * label: network node (brain region- gene
 combination, or circulating T) * x: x coordinate  * y: y coordinate ##
 Code/software George and Rosvall H&B 2025.R  run with R (version
 4.1.1)  Packages required are specified within the above R script.