Understanding the Dynamics of Sex-Specific Responses Driven by Grassland Management: Using Syrphids as a Model Insect Group

Abstract

Grassland ecosystems, managed by various grassland managements strategies, are the world’s most important land use. However, insect’s sex-specific responses within the context of grassland management have never been considered before. Therefore, our aim was to expand the understanding to the dynamics of grassland managements that drive sex-specific responses by using syrphids as a model insect group. We hypothesize that (1) male and female syrphids exhibit differential habitat preferences in grassland managements, (2) abundance and activity of male and female syrphid levels are influenced by vegetation structure in grassland habitats. Extensive and intensive grassland exhibited significantly different male and female syrphid abundance compared to abandoned grassland. Surprisingly, grassland management had a significant impact on male syrphids richness only, not on female. Flower cover significantly increased male and female syrphid abundance and richness. However, plant height significantly increased female syrphid abundance and richness only. Interestingly, abandoned grassland supports a higher amount of unique female syrphids than male syrphids. The dynamics of grassland management are not unidirectional, but they are multifaceted and multidirectional. Considering the importance of sex-specific responses by insects can provide a more comprehensive understanding of dynamics of grassland managements.

1. Introduction

Grassland ecosystems constitute the most significant land use in the world, accounting for one-third of total land area [1,2]. Permanent grasslands account for 34% of Europe’s total agricultural land area [3], and are defined as land that has been used to cultivate grass or herbaceous fodder, forage, or energy crops for five years or more [4]. Anthropogenic change is reshaping Europe’s diverse grasslands [5,6], including land abandonment [7]. As a result, practically all European countries report a decrease in grassland area and a related loss of biodiversity [8,9]. This has raised concerns that European grasslands may be unable to provide key ecological functions such as pollination [10,11].

The conservation and enhancement of European grassland’s biodiversity and ecological services has been prioritized in national and international policy and research programs [12,13]. In most European countries, biodiversity in grasslands is threatened by two opposing trends: intensification and abandonment [14,15]. Both have led to a reduction in the number of plant species [16]. Alternatively, low-intensity mowing has been utilized to preserve biodiversity, mainly insects, in semi-natural grasslands [17].

Insects constitute a significant proportion of terrestrial biodiversity [18], and their presence or absence can provide insights into the overall health and diversity of grassland habitats [19]. Changes in insect populations can reflect alterations in habitat conditions, including changes in vegetation structure, availability of food resources, and the presence of other insects [20]. Monitoring insect populations can therefore help to assess the overall biodiversity and ecological integrity of grasslands [21].

There are many studies on the abundance, richness, and composition of insects in grassland [22,23,24,25]. By studying these metrics, researchers gained insights into the ecological dynamics [26], community interactions [27], and responses of insects to various factors such as land management practices [28], habitat quality [29], and environmental changes [30]. These studies contribute to our understanding of grassland ecology and help for developing effective conservation and management strategies for maintaining insect biodiversity and ecosystem health in grassland habitats. However, it is important to note that insect’s sex-specific responses within the context of grassland management have never been considered before.

Sex-specific responses in insects refer to the different behaviors, physiological characteristics, and ecological roles exhibited by males and females of the same insect species [31]. Grassland management, which involves modifying and maintaining the environment to support specific species or communities, can have significant impacts on insect populations, including their sex-specific responses [32]. In many insect species, males and females display different behaviors related to mating, foraging, and territoriality [33]. For example, male insects may exhibit courtship behaviors to attract females, while females might have specific behaviors related to egg-laying and parental care. Grassland management practices can influence the availability of resources for mating and reproductive success, impacting the overall population dynamics of the species [34].

We used syrphids as a model insect group to study sex-specific responses to different grassland management. Due to adaptability, mimicry and varied feeding habits, syrphids are a diverse family of flies within the order Diptera, and they are often abundant and easily recognizable in grassland habitats due to sexual dimorphism [35]. Grassland management practices significantly influence the life cycle of syrphids in various ways. Mowing, grazing, or burning can impact the availability of suitable habitats for syrphids at different life stages, affecting overwintering sites for adults, larvae, and pupae [36]. Studying syrphid sex-specific responses to grassland management is crucial for understanding how different management practices impact the behavior, ecological roles and abundance of males and females within the syrphid population. Referring to the last aspect, our aim was to expand the understanding of the dynamics of grassland management that drives sex-specific responses using syrphids. We hypothesize that (1) male and female syrphids exhibit differential habitat preferences in grasslands, and that (2) abundance and richness of male and female syrphids are influenced by vegetation flower cover and plant height in grassland habitats.

2. Materials and Methods

2.1. Study Sites

The field sampling was carried out in the alpine mountains, in the region of Amstetten, Scheibbs and Melk in the province of Lower Austria, spanning a total area of 19,186 km². Approximately 60% of the land is dedicated to cattle farming, which dominates the agricultural sector. To ensure comprehensive data collection, we carefully considered several factors when choosing our study sites. Primarily, we focused on capturing a uniform range of elevations within the alpine grassland to capture the full spectrum of syrphid diversity patterns in study sites [37]. This approach allowed us to account for potential variations in syrphid communities driven by different grassland types at the same elevation (~989 m). We chose two types of certified organic grassland (intensive and extensive), and abandoned grasslands that were located near to certified organic grassland (Figure 1). On south-facing slopes, we surveyed 10 replicates of each abandoned, extensive and intensive grassland (n = 30). The selected extensive grasslands were not fertilized and only mown once or twice a year. Intensive grasses were mown four times per year at most. Management of the abandoned grasslands has been ceased for at least 10–20 years. All study sites were imbedded in a comparable landscape matrix and located in similar mesic and altitudinal zones. Vegetation in intensive grasslands was dominated by legumes and grasses indicating nutrient-rich conditions (e.g., Trifolium repens Lolium perenne), whereas that of extensive grassland was dominated by grasses and legumes indicating nutrient-poorer conditions (e.g., Bromus erectus, Lotus corniculatus), and the herbs Ajuga reptans and Cruciata laevipes were dominant in abandoned grassland.

2.2. Syrphid Sampling

Syrphids were sampled eight times during the flowering season between May to August 2021 and 2022. We chose this time because it represents the period when most plants are in bloom, which indicates the maximum development of the vegetation [38]. Syrphids were sampled using two different methods: line transect and observation plot method [39]. For each study site (abandoned, extensive, intensive), we established three line transects (a total of 90 sweeps each), measuring 30 × 2 m each. Transects were placed with a minimum distance of 20 m between them, and towards the center of a study site. We used the observation plot method to create five 4 m² plots, each 10 m from a fixed starting point per study site. Each plot was examined for 10 min, and rapidly moving syrphids were captured using an entomological hand net. To prevent sampling bias, all study sites were randomly sampled between 9 a.m. and 6 p.m. Syrphid sampling was limited to sunny days, as it is well known that the weather has a significant impact on syrphid activity [40]. Syrphids collected during observation plot and line transect method were sorted, based on sexes, and stored in 70% ethanol. Later, syrphid identification was carried out with the help of identification keys [41,42].

2.3. Vegetation Survey

Flower cover and plant height (from base until top) were measured as a predictor for syrphid abundance and richness between May and August 2021 and 2022. On each study site, we laid a wooden grid of 1 × 1 m size that was divided into 25 squares [43]. The proportion of total number of squares with at least one nectar-producing flower were counted. A measuring tape was inserted five times vertically up to the soil surface to measure plant height per study site.

2.4. Statistical Analysis

To test whether male and female syrphid abundance and species richness showed sex-specific responses to the grassland managements, the function glmer from package lme4 was used to create generalized linear mixed models (GLMMs) [44]. Poisson family GLMMs were applied because the response variables (abundance and species richness) were count data. We aggregated all plots (five observation plots) and transects (three line transects) for each study site, and replications were added as a group-level variable. The variable replication was used to fit the GLMM models with a varying-intercept group effect. The dispersion_glmer function of the blmeco package and the dispersiontest function from the AER package [45,46] were used to check for overdispersion (the residual deviation was more than the degree of freedom) showed by Poisson GLMMs. An additional observation-level random effect was added to a model in cases of overdispersion [47]. If there were significant differences across study sites, Tukey’s post hoc pairwise comparisons were performed using glht function from package multcomp. Later, Nakagawa and Schielzeth’s [48] method was used to determine marginal R² (R²m) and conditional R² (R²c) for mixed models using the MuMIn package.

To examine how syrphid species, based on sexes, overlapped among study grassland managements, we created Venn diagrams from plotVenn package that used nVenn algorithm. Furthermore, we used GLMMs to examine how studied predictor variables (flower cover and plant height) influenced sex-specific abundance and species richness of syrphids. The response variables were male and female syrphid abundance and species richness, and fixed factors were flower cover and plant height for each study site. Replications were added as a group-level variable. Additionally, using the R package car, we computed the variance inflation factors (VIFs) to check for multicollinearity between predictor variables [49]. In the models, any variables with a VIF over 5 were eliminated. We calculated our GLMs using these data as a basis.

Species assemblages in three grassland managements were calculated using Non-metric Multidimensional Scaling (NMDS) [50]. We pooled all sampling data (five observation plots and three line transects) for each study site. The species abundance was Hellinger-transformed to avoid the common zero problem. The function adonis in the R package vegan was used to generate a PERMANOVA (Bray–Curtis dissimilarities, 999 permutations) (as performed by Boetzl [51]). Using the function betadisper, data were examined for equal multivariate dispersion. Additionally, to check for variations in species assemblages amongst study sites (i.e., abandoned, extensive, intensive), multilevel pairwise comparison using adonis was performed (pairwise.adonis). The R program version 3.5.1 was used to carry out all statistical analyses [52], and model results were stated using the standards established by Zuur and Ieno [53].

3. Results

In the studied grasslands, we collected 2315 syrphid individuals from 93 species over the sample period (2021 and 2022). For the analyses, we only used males (1069 individuals and 63 species) and females (1246 individuals and 70 species) that had clearly distinguished sex-specific characteristics (Appendix A 

Table A1. List of studied male and female syrphid abundance and species richness in studied grassland managements. Abundance is given in numbers, while empty space indicates absence.

Syrphid (Male)
	Species	Abandoned	Extensive	Intensive
1	Baccha elongata	1
2	Cheilosia bergenstammi			1
3	Cheilosia chrysocoma	1
4	Cheilosia grossa	1
5	Cheilosia impressa	1	1
6	Cheilosia lasiopa			1
7	Cheilosia latifrons		1
8	Cheilosia nasutula			1
9	Cheilosia soror	1
10	Cheilosia sp.	2	1	1
11	Cheilosia variabilis			1
12	Cheilosia vernalis	5		1
13	Chrysogaster solstitialis		1
14	Chrysotoxum bicinctum	1		2
15	Chrysotoxum elegans		1
16	Chrysotoxum festivum		1	3
17	Dasysyrphus albostriatus		1
18	Episyrphus balteatus	11	30	9
19	Eristalinus aeneus		2
20	Eristalis arbustorum	1	8
21	Eristalis nemorum		1
22	Eristalis pertinax	1
23	Eristalis tenax	19	28	31
24	Eumerus ornatus		1
25	Eumerus sp.		1
26	Eumerus strigatus			1
27	Eupeodes bucculatus			2
28	Eupeodes corollae	2	7	8
29	Eupeodes lapponicus	3	2	9
30	Eupeodes latifasciatus		1	1
31	Eupeodes luniger	1		3
32	Eupeodes lapponicus	2	3	2
33	Leucozona laternaria			1
34	Melanostoma mellinum	15	35	39
35	Merodon aberrans		1
36	Myathropa florea	71	80	48
37	Neoascia podagrica	1		3
38	Orthonevra nobilis		1
39	Paragus haemorrhous	1	1
40	Parasyrphus lineolus		1
41	Pipizella sp.	8
42	Pipizella viduata	19	43	29
43	Pipizella viduata	1	2	3
44	Pipizella virens	15	42	23
45	Platycheirus albimanus	1	1	2
46	Platycheirus podagratus	1
47	Platycheirus sp.			1
48	Rhingia campestris	3	1
49	Scaeva pyrastri		2	2
50	Scaeva selenitica	5	1	6
51	Sphaerophoria batava	2		2
52	Sphaerophoria interrupta	6	6	16
53	Sphaerophoria scripta	13	60	34
54	Sphaerophoria taeniata	6	41	58
55	Sphegina clunipes	1
56	Syritta pipiens	13	8	2
57	Syritta pipiens		1
58	Syrphus ribesii	2	3	2
59	Syrphus torvus	7	21	17
60	Syrphus vitripennis	2	2	4
61	Xanthandrus comtus	1
62	Xanthogramma pedissequum			1
63	Xylota segnis	3	2	3
Syrphid (Female)
1	Baccha elongata	5
2	Brachyopa scutellaris			1
3	Cheilosia albitarsis	3	4	1
4	Cheilosia antiqua		1	1
5	Cheilosia fraterna	3
6	Cheilosia latifrons		1
7	Cheilosia pagana			2
8	Cheilosia sp.	1	2	2
9	Chrysogaster solstitialis		9	4
10	Chrysogaster virescens	1	2
11	Chrysotoxum bicinctum	2	2	3
12	Chrysotoxum cautum	2
13	Chrysotoxum elegans	1
14	Chrysotoxum festivum	2	2	2
15	Chrysotoxum octomaculatum		1
16	Didea alneti		1
17	Epistrophe eligans	1
18	Episyrphus balteatus	29	37	32
19	Eristalinus aeneus		3
20	Eristalinus sepulchralis	1
21	Eristalis arbustorum	5	6	1
22	Eristalis nemorum		1
23	Eristalis pertinax	1
24	Eristalis tenax	29	33	27
25	Eumerus tuberculatus		1
26	Eupeodes bucculatus	1	1	1
27	Eupeodes corollae	2	2	3
28	Eupeodes lapponicus	4	3	4
29	Eupeodes latifasciatus		2	1
30	Eupeodes luniger	2	2	2
31	Eupeodes nitens			1
32	Eupeodes lapponicus	1
33	Helophilus hybridus		1
34	Helophilus pendulus		1
35	Helophilus trivittatus		2	2
36	Melanostoma mellinum	44	107	151
37	Melanostoma scalare	4	4	8
38	Meligramma cincta		1	1
39	Myathropa florea	39	23	18
40	Neoascia obliqua	1		2
41	Neoascia podagrica	1	1	5
42	Paragus sp.	6	2
43	Parasyrphus annulatus		1
44	Parasyrphus lineolus	1
45	Philhelius pedissequus	1
46	Pipiza noctiluca	4	1	2
47	Pipizella sp.	1
48	Pipizella viduata	16	34	22
49	Pipizella viduata	1	1	3
50	Pipizella virens	15	19	18
51	Platycheirus albimanus	9	9	16
52	Platycheirus angustatus		4
53	Platycheirus clypeatus	1	1
54	Platycheirus scutatus	1
55	Rhingia campestris	9	1	2
56	Scaeva pyrastri	1	1	2
57	Scaeva selenitica	3		1
58	Sphaerophoria scripta	29	99	94
59	Sphaerophoria taeniata		2
60	Syritta pipiens	5	4	5
61	Syrphus ribesii	2	6
62	Syrphus torvus	4	14	23
63	Syrphus vitripennis	4	6	6
64	Volucella inanis	1
65	Volucella pellucens	2
66	Xanthogramma laetum	1
67	Xanthogramma pedissequum	2	1
68	Xylota segnis	3	2	1
69	Xylota tarda	2
70	Xylota xanthocnema		2
71	Xylota sylvarum			1

). Out of the total male syrphids, 250 individuals and 39 species were in abandoned, 446 individuals and 38 species were in extensive, and 373 individuals and 37 species were in intensive grassland. Considering females, 309 individuals and 49 species were in abandoned, 466 individuals and 48 species were in extensive, and 471 individuals and 37 species were in intensive grassland. The most abundant male species were Myathropa florea in abandoned (28.40%), extensive (17.94%), and intensive grassland (12.87%). However, female Melanostoma mellinum was most abundant in abandoned (14.24%), extensive (22.96%), and in intensive grassland (32%).

Extensive and intensive grassland exhibited significantly different male and female syrphid abundance compared to abandoned grassland (Figure 2;

Table 1. Generalized linear mixed effects models (GLMM) and Tukey’s post hoc pair-wise testing for variations in male and female syrphids among studied grassland managements (abandoned—as intercept, extensive, and intensive). Significant p values are shown in bold.

Syrphid (Male)			Estimate	Std. Error	z	p	95% CI
abundance	GLMM	abandoned (Intercept)	1.009	0.114	8.796	<0.001	2.19–3.44
		extensive	0.462	0.148	3.109	0.002	1.19–2.13
		intensive	0.422	0.154	2.743	0.006	1.13–2.06
		Dispersion	0.96	R2m	0.057	R2c	0.726
	Tukey’s post hoc pairwise comparisons	extensive × abandoned	0.462	0.148	3.109	0.005
		intensive × abandoned	0.422	0.154	2.743	0.016
		intensive × extensive	−0.039	0.144	−0.273	0.959
richness
	GLMM	abandoned (Intercept)	0.886	0.103	8.592	<0.001	1.98–2.97
		extensive	0.489	0.131	3.s718	<0.001	1.26–2.11
		intensive	0.493	0.135	3.652	<0.001	1.26–2.13
		Dispersion	1.277	R2m	0.116	R2c	0.406
	Tukey’s post hoc pairwise comparisons	extensive × abandoned	0.489	0.131	3.718	<0.001
		intensive × abandoned	0.493	0.135	3.652	<0.001
		intensive × extensive	0.003	0.123	0.03	0.999
Syrphid (Female)
abundance	GLMM	abandoned (Intercept)	1.259	0.098	12.822	<0.001	2.91–4.27
		extensive	0.341	0.13	2.626	0.009	1.09–1.82
		intensive	0.305	0.129	2.357	0.018	1.05–1.75
		Dispersion	0.99	R2m	0.044	R2c	0.619
	Tukey’s post hoc pairwise comparisons	extensive × abandoned	0.341	0.13	2.626	0.023
		intensive × abandoned	0.305	0.129	2.357	0.048
		intensive × extensive	−0.036	0.123	−0.296	0.953
richness
	GLMM	abandoned (Intercept)	1.212	0.085	14.239	<0.001	2.85–3.97
		extensive	0.255	0.112	2.266	0.023	1.04–1.61
		intensive	0.241	0.112	2.151	0.032	1.02–1.59
		Dispersion	1.18	R2m	0.038	R2c	0.311
	Tukey’s post hoc pairwise comparisons	extensive × abandoned	0.255	0.112	2.266	0.061
		intensive × abandoned	0.241	0.112	2.151	0.079
		intensive × extensive	−0.014	0.107	−0.134	0.99

Dispersion: 0.75 to 1.4; CI = 95% confidence intervals; R²m = marginal R²; R²c = conditional R².

). There was no significant difference between extensive and intensive grassland managements for male and female syrphid abundance and richness (Figure 2; Table 1). Flower cover within grassland management significantly increased male and female syrphid abundance and richness. Additionally, plant height significantly increased female syrphid abundance and richness (

Table 2. Generalized linear mixed models (GLMMs) showing the effects of flower cover and plant height on male and female syrphids abundance and species richness. Significant p values are shown in bold.

Syrphid (Male)		Estimate	Std. Error	z	p	95% CI
abundance	(Intercept)	0.977513	0.194999	5.013	<0.001	1.81–3.90
	Flower cover	0.046236	0.009983	4.631	<0.001	1.03–1.07
	Plant height	0.003303	0.002554	1.293	0.196	1.00–1.01
	R2m	0.121	R2c	0.193	Dispersion	0.9784	VIF	1.003
richness	(Intercept)	0.776352	0.141685	5.479	<0.001	1.65–2.87
	Flower cover	0.030096	0.007167	4.199	<0.001	1.02–1.05
	Plant height	0.001823	0.001883	0.968	0.333	1.00–1.01
	R2m	0.099	R2c	0.162	Dispersion	0.9572	VIF	1.005
Syrphid (Female)
abundance	(Intercept)	1.170764	0.139302	8.405	<0.001	2.45–4.24
	Flower cover	0.039004	0.006846	5.697	<0.001	1.03–1.05
	Plant height	0.005217	0.001911	2.73	0.006	1.00–1.01
	R2m	0.172	R2c	0.232	Dispersion	1.006	VIF	1.001
richness	(Intercept)	0.834297	0.127584	6.539	<0.001	1.79–2.96
	Flower cover	0.024706	0.005777	4.277	<0.001	1.01–1.04
	Plant height	0.00496	0.00155	3.201	0.001	1.00–1.01
	R2m	0.139	R2c	0.1975	Dispersion	0.906	VIF	1.003

Dispersion: 0.75 to 1.4; CI = 95% confidence intervals; R²m = marginal R²; R²c = conditional R².; VIF= variance inflation factor.

; Appendix A Figure A1).

Overall, about an equal amount of male and female syrphids were shared within grassland managements (32.3% syrphid male; 37.1% syrphid female; Figure 3). Interestingly, abandoned grassland supports a higher amount of female (22.9%) compared to male syrphids (14.5%). On the contrary, intensive grassland had a higher proportion of males (14.5%) than females (5.7%) (Figure 3). Grassland management had similar male syrphid assemblages (Appendix A Figure A2 and

Table A2. PERMANOVA (Pairwise-adonis) for male and female syrphids in studied grassland managements, i.e., abandoned, extensive and intensive grassland. Significant p-values (<0.05) are marked in bold.

Syrphid (Male)		Df	Sum Sq	R2	F	p
Adonis	Management regimes	2	0.357	0.082	1.213	0.215
	Residual	27	3.976	0.917
	Total	29	4.333	1
Pairwise Adonis		F. Model	R2	p	Adjusted p
	abandoned × extensive	1.016	0.053	0.449	1
	abandoned × intensive	1.431	0.073	0.127	0.381
	extensive × intensive	1.162	0.06	0.318	0.954
Syrphid (Female)
Adonis	Management regimes	2	0.445	0.102	1.533	0.033
	Residual	27	3.919	0.897
	Total	29	4.364	1
Pairwise Adonis		F. Model	R2	p	Adjusted p
	abandoned × extensive	1.906	0.095	0.008	0.024
	abandoned × intensive	1.681	0.085	0.048	0.144
	extensive × intensive	0.841	0.044	0.621	1

). For female syrphid assemblages, abandoned grassland differed significantly from extensive grassland (Appendix A Figure A2 and Table A2).

4. Discussion

It is known that extensive grasslands support high biodiversity, including an abundance of pollinators like syrphids [54]. This increase in biodiversity is more noticeable when pollinator diversity in extensive grassland was studied compared to abandoned grassland [55]. Furthermore, the high intensity of grassland management is expected to result in a decrease in pollinator diversity [56]. There could be several reasons why extensive and intensive grassland management had a similar effect on male and female syrphid abundance:

• Scale and timing of management: The scale and timing of the grassland management practices may have aligned with the life cycle and movement patterns of syrphids. Syrphids have different activity periods [57], migration patterns [58], and breeding requirements [59]. If the grassland management practices consider these factors, it could have limited their extent in influencing syrphid male and female abundance.
• Habitat connectivity: Syrphids often require suitable habitats in close proximity to each other to support their abundance [60,61]. If the grassland management practices create or maintain sufficient linear connectivity between different patches of suitable habitat, then it could have limited the movement and dispersal of syrphid males and females, ultimately equalizing their abundance.
• Resource availability: Grassland management practices can directly influence the availability of resources that syrphids rely on, such as nectar, pollen, and suitable breeding sites [62]. For example, the maintenance of diverse plant communities in extensive grassland could enhance the availability of nectar and pollen resources, benefiting both male and female syrphids and potentially increasing their abundance in nearby intensive grassland.

Surprisingly, female syrphid richness did not differ among the grassland management practices. The richness of female syrphids could be influenced by a variety of factors, including flower cover, habitat structure, microclimate, and disturbance levels [60,63,64,65]. However, we do not know which factor led to a consistent pattern of female syrphid richness in the studied grassland management practices.

The increase in flower cover within grassland management practices can significantly enhance the abundance and richness of male and female syrphids. Increasing flower cover may lead to favorable foraging opportunities [66], and improves the availability of oviposition sites [67] for females. Females of some syrphid species exhibit preferences for specific plant heights based on their host plant choices. Certain syrphid species prefer taller plants as preferred oviposition sites [68]. Thus, grassland management practices, especially abandoned and extensive grassland, promoting taller plants may attract a greater number of species with specific host plant preferences, thereby potentially increasing the richness of female syrphids. Furthermore, a plant’s height can support a greater number of prey insects, such as aphids (Hemiptera) and thrips (Thysanoptera) [69], which are an important food source for the larvae of female syrphids. More abundant prey availability can support larger populations of female syrphids as they actively search for suitable host plants to deposit their eggs [70]. Consequently, an increase in plant height can indirectly contribute to the abundance and richness of female syrphids through enhanced prey availability.

When grasslands are abandoned and left undisturbed, they can undergo changes in vegetation composition, structure, and ecological dynamics [71]. As abandoned grasslands undergo natural succession, with changes in plant communities over time, the syrphid assemblages can also change [72]. Early successional stages may attract certain syrphid species (i.e., Baccha elongata) that prefer open, grassy habitats, while later successional stages with increased shrub or tree cover may favor other syrphid species (i.e., Chrysotoxum bicinctum). Interestingly, all grassland managements exhibited similar amounts of unique male and female syrphid species. The presence and abundance of syrphid species in a particular area are influenced by the regional species pool as mentioned in [73,74]. It is possible that the grassland management practices were implemented within a region with a relatively consistent species pool, and the number of unique species may not vary significantly between the different management types. In such cases, the large number of species would remain similar regardless of the grassland management practices.

However, abandoned and extensive grasslands are often characterized by lower levels of human disturbance compared to intensive management practices [75]. Reduced disturbance can create more favorable conditions for certain female syrphids, as they may be more sensitive to disturbances during oviposition and larval development. The decreased disturbance levels in abandoned and extensive grasslands may attract a higher abundance or diversity of unique female syrphids, compared to intensive management types.

5. Conclusions

The dynamics of grassland managements are not unidirectional, but they are multifaceted and multidirectional. In many studies, insect species richness, abundance and assemblage patterns were taken into consideration. In our study, we found a sex-specific response of syrphids to abandoned, extensive and intensive grasslands. Some limitations of understanding the dynamics of sex-specific responses lies in the potential lack of generalizability beyond the specific context of syrphid ecology and grassland ecosystems. While syrphids offer valuable insights into insect behavior and community dynamics, extrapolating findings to broader insect taxa or ecosystems may be challenging due to inherent differences in species composition, habitat characteristics, and management practices. Additionally, the complexity of grassland ecosystems, including spatial heterogeneity and temporal variability in environmental conditions, can introduce confounding factors that complicate the interpretation of sex-specific responses. Thus, considering and understanding these sex-specific responses is challenging for effective ecosystem management and conservation efforts. Studying the sex-specific responses can help in understanding the implications for population dynamics and colonization abilities of insects in fragmented landscapes. Considering the importance of sex-specific responses by insects can provide a more comprehensive understanding of dynamics of grassland managements. By doing so, we can gain deeper insights into population dynamics, species interactions, and conservation strategies for insect communities.